PSEB 11th Class Physics Important Questions Chapter 8 Gravitation

Punjab State Board PSEB 11th Class Physics Important Questions Chapter 8 Gravitation Important Questions and Answers.

PSEB 11th Class Physics Important Questions Chapter 8 Gravitation

Very Short Answer Type Questions

Question 1.
By which law is the Kepler’s law of areas identical?
Answer:
The law of conservation of angular momentum.

Question 2.
Draw areal velocity versus time graph for mars. (NCERT Exemplar)
Answer:
Areal velocity of planet revolving around the Sun is constant with time (Kepler’s second law).
PSEB 11th Class Physics Important Questions Chapter 8 Gravitation 1

Question 3.
At what factor between the two particles gravitational force does not depend?
Answer:
Gravitational force does not depend upon the medium between the two particles.

Question 4.
Two particles of masses m1 and m2 attract each other gravitationally and are set in motion under the influence of the gravitational force? Will the centre of mass move?
Answer:
Since the gravitational force is an internal force, therefore the centre of mass would not move.

Question 5.
Work done in moving a particle round a closed path under the action of gravitation force is zero. Why?
Answer:
Gravitational force is a conservative force which means that work done by it, is independent of path followed.

Question 6.
What would happen if the force of gravity were to disappear suddenly?
Answer:
The universe would collapse. We would be thrown away because of the centrifugal force. Eating, drinking and in fact all activities would become impossible.

Question 7.
Why a body weighs more at poles and less at equator?
Answer:
The value of g is more at poles than at the equator. Therefore, a body weighs more at poles than at equator.

Question 8.
Give a method for the determination of the mass of the moon.
Solution:
Soli By making use of the relation, gm = \(\frac{G M_{m}}{R_{m}^{2}} \)

Short Answer Type Questions

Question 1.
A planet moving along an elliptical orbit is closest to the Sim at a distance r1 and farthest away at a distance of r2.
If v1 and v2 are the linear velocities at these points respectively, then find the ratio \(\frac{v_{1}}{v_{2}}\).
Solution:
From the law of conservation of angular momentum
mr1v1 = mr2v2
⇒ r1v1 = r2v2 or
\(\frac{v_{1}}{v_{2}}=\frac{r_{2}}{r_{1}}\)

Question 2.
A mass M is broken into two parts, m and (M – m). How is m related to M so that the gravitational force between two parts is maximum?
Solution:
Let =m,m2 =M – m
F = G\(\frac{m(M-m)}{r^{2}}=\frac{G}{r^{2}}\left(M m-m^{2}\right)\)
Differentiating w.r:t. m, \(\frac{d F}{d m}=\frac{G}{r^{2}}(M-2 m)\)
For F to be maximum, \(\frac{d F}{d m}\) = 0
PSEB 11th Class Physics Important Questions Chapter 8 Gravitation 2
m1 = m2 = M/2

Question 3.
Two stationary particles of masses M1 and M2 are a distance d apart. A third particle lying on the line joining the particles, experiences no resultant gravitational force. What is the distance of this particle from M1?
Solution:
The force on m towards Mi is F =G \(\frac{M_{1} m}{r^{2}}\)
The force on m towards Mi is F = G \(\frac{M_{2} m}{(d-r)^{2}} \)

Equating two forces, we have
PSEB 11th Class Physics Important Questions Chapter 8 Gravitation 4
So, distance of an particle from m is . r = d
r = d \(\left(\frac{\sqrt{M_{1}}}{\sqrt{M_{1}}+\sqrt{M_{2}}}\right)\).

Question 4.
Aspherical planet has mass Mp and clinometer Dp. A particle of mass m falling freely near the surface of this planet will experience an acceleration due to gravity, equal to whom?
Solution:
Force is given by
F = \(-\frac{G M m}{R^{2}}=\frac{G M_{p} m}{\left(D_{P} / 2\right)^{2}}=\frac{4 G M_{P} m}{D_{P}^{2}}\)
\(\frac{F}{m}=\frac{4 G M_{P}}{D_{P}^{2}}\)

Question 5.
What is the gravitational potential energy of a body at height h from the Earth surface?
Solution:
Gravitational potential energy, i. e.,
Uh = \(-\frac{G M m}{R+h}=-\frac{g R^{2} m}{R+h}\)
[where g = \(\frac{G M}{R^{2}}\) ]
= – \(\frac{g R^{2} m}{R\left(1+\frac{h}{R}\right)}=-\frac{m g R}{1+\frac{h}{R}}\)
.
Question 6.
An artificial satellite is moving in a circular orbit around the Earth with a speed equal to half the magnitude of escape velocity from Earth.
Determine
(i) the height of satellite above Earth’s surface.
(ii) if the satellite is suddenly stopped, find the speed with
which the satellite will hit the Earth’s surface after falling down.
Solution:
Escape velocity = \(\sqrt{2 g R}\), where g is acceleration due to gravity on surface of Earth and R the radius of Earth.
Orbital velocity = \(\frac{1}{2} v_{e}=\frac{1}{2} \sqrt{2 g R}=\sqrt{\frac{g R}{2}} \) …………………. (i)

(i) If h is the height of satellite above Earth
PSEB 11th Class Physics Important Questions Chapter 8 Gravitation 5
h=R
(ii) If the satellite is stopped in orbit, the kinetic energy is zero and its
potential energy is – \(\frac{G M m}{2 R}\)
Total energy =-\(\frac{G M m}{2 R}\)

Let v be its velocity when it reaches the Earth.
Hence the kinetic energy = \(\frac{1}{2} m v^{2}\)
Potential energy = – \(\frac{G M m}{2 R}\)
PSEB 11th Class Physics Important Questions Chapter 8 Gravitation 6

Question 7.
Why do different planets have different escape velocities?
Solution:
Escape velocity, v = \(\sqrt{2 g R}=\sqrt{\frac{2 G M}{R}}\)
Thus escape velocity of a planet depends upon (i) its mass (M) and
(ii) its size (R).
As different planets have different masses and sizes, so they have different escape velocities.

Question 8.
Under what circumstances would your weight become zero?
Answer:
The weight will become zero under the following circumstances
(i) during free fall
(ii) at the centre of the Earth
(iii) in an artificial satellite
(iv) at a point where gravitational pull of Earth is equal to the gravitational pull of the Moon.

Long Answer Type Questions

Question 1.
A mass m is placed at P, a distance h along the normal through the centre O of a thin circular ring of mass M and radius r. If the mass is removed further away such that OP becomes 2h, by what factor the force of gravitation will decrease, if h = r? (NCERT Exemplar)
PSEB 11th Class Physics Important Questions Chapter 8 Gravitation 7
Solution:
Consider a small element of the ring of mass dM, gravitational force between dM and m, distance x apart in figure i.e.,
dF = \(\frac{G(d m) m}{x^{2}}\)
PSEB 11th Class Physics Important Questions Chapter 8 Gravitation 8
dF can be resolved into two rectangular components.
(i) dF cos θ along PO and
(ii) dF sinθ perpendicular to PO (given figure)
The total force (F) between the ring and mass (m) can be obtained by integrating the effects of all the elements forming the ring, whereas all the components perpendicular to PO cancel out i.e., ∫dFsinθ=O, the component along PO add together to give F i.e.,
PSEB 11th Class Physics Important Questions Chapter 8 Gravitation 9

Question 2.
A satellite is to be placed in equatorial geostationary orbit around the Earth for communication.
(i) Calculate height of such a satellite.
(ii) Find out the minimum number of satellites that are needed to cover entire Earth so that at least one of satellite is visible from any point on the equator.
[M = 6 x 10 24 kg, R = 6400 km, T = 24 h, G = 6.67 x 10-11SI (NCERT Exemplar)
Solution:
(i) As, according co Kepler’s third law, we get
T2 = \(\frac{4 \pi^{2} r^{3}}{G M}\)
⇒ r = \( \left(\frac{G M T^{2}}{4 \pi^{2}}\right)^{1 / 3}\)
PSEB 11th Class Physics Important Questions Chapter 8 Gravitation 10
As we known =R +h
h=r-R
h=4.23 x 107 m – 6.4 x 106 m
h = 3.59 x 107 m

(ii) In ΔOES,cos θ = \(\frac{O A}{O S}=\frac{R}{R+h}\)
= \(\frac{1}{\left(1+\frac{h}{R}\right)}\)
= \(\frac{1}{(1+5.609)}\)
=0.1513
(as,\(\frac{h}{R}=\frac{3.59 \times 10^{7} \mathrm{~m}}{6.4 \times 10^{6} \mathrm{~m}}\) = 5.609)
where, θ ≈ 81° or 2θ = 162°
Number of satellites required to cover entire the Earth.
= \(\frac{360^{\circ}}{162^{\circ}}=2.2\) ≈ 3.

PSEB 11th Class Biology Important Questions Chapter 21 Neural Control and Coordination

Punjab State Board PSEB 11th Class Biology Important Questions Chapter 21 Neural Control and Coordination Important Questions and Answers.

PSEB 11th Class Biology Important Questions Chapter 21 Neural Control and Coordination

Very Short Answer Type Questions

Question 1.
Which part of the neuron is considered as afferent process?
Answer:
Dendrites conduct nerve impulses towards the cell body and are called afferent processes (receiving processes).

Question 2.
Give the name of the chemicals, which are released at the synaptic junction. [NCERT Exemplar]
Answer:
Neurotransmitters.

Question 3.
Name the small protein tubular structures between the two neurons.
Answer:
Gap junctions.

Question 4.
Which is the largest and most complex of all, the parts of the human brain?
Answer:
Cerebrum.

Question 5.
What is the role of afferent nerve fibers in the neural system?
Answer:
It transmits impulse (sensory) from tissues/organs to the CNS and form, the sensory or afferent pathway.

PSEB 11th Class Biology Important Questions Chapter 21 Neural Control and Coordination

Question 6.
How does the efferent fibers work?
Answer:
The efferent nerve fibers transmit motor impulses from CNS to the concerned tissues/organs and form the motor or efferent pathway.

Question 7.
The autonomic neural system is considered as involuntary neural system. Why?
Answer:
This system transmits impulses from the CNS to the involuntary organs and smooth muscles of the body. So, it is also called involuntary neural system.

Question 8.
How does the somatic neural system works?
Answer:
The somatic neural system controls the movements of the body by acting on the skeletal muscles (i.e., relays voluntary impulses from the CNS to skeletal muscles).

Question 9.
Give the name of the covering that maintains the shape of the eyeball.
Answer:
Sclera (outermost layer).

Question 10.
Which is the bluish (pigmented) layer present beneath the sclera?
Answer:
Choroid.

Question 11.
Which part of our body helps us in maintaining the body balance?
Answer:
Ears.

Question 12.
Which of the photoreceptors is responsible for twilight vision?
Answer:
Rods.

Short Answer Type Questions

Question 1.
Give a brief description of the neural system.
Answer:
The neural system is composed of specialized cells called neurons. It detects stimuli and transmits neural signals. The neural system of complex animals is composed of two parts, viz. central neural system and peripheral neural system. The brain and nerve cord comprise the central neural system and other nerves comprise the peripheral neural system.

Question 2.
Explain parasympathetic neural system.
Answer:
The parasympathetic neural system is part of autonomic neural system. This system has some sort of inhibitory effect. The inhibitory effect minimises the over-functioning of certain functions. Functions, like salivating, digestion, are under control of parasympathetic neural system.

Question 3.
Give a description of the structure of neuron.
Answer:
A neuron is a microscopic structure composed of three major parts, namely, cell body, dendrites and axon.
Cell Body: The cell body contains cytoplasm with typical cell organelles and certain granular bodies called Nissl’s granules.

Dendrites: Short fibers which branch repeatedly, and project out of the cell body also contain Nissl’s granules and are called dendrites. These fibers transmit impulses towards the cell body.

Axon: The axon is a long fibre, the distal end of which is branched. Each branch terminates as a bulb-like structure called synaptic knob which possess synaptic vesicles containing chemicals called neurotransmitters. The axons transmit nerve impulses away from the cell body to a synapse or to a neuromuscular junction.

PSEB 11th Class Biology Important Questions Chapter 21 Neural Control and Coordination

Question 4.
Describe reflex action.
Answer:
The entire process of response to a peripheral neural stimulation, that occurs involuntarily, i.e., without conscious effort or thought and requires the involvement of a part of the central neural system is called a reflex action.
The reflex pathway comprises at least one afferent neuron (receptor) and one efferent (effector or excitor) neuron appropriately arranged in a series.

The afferent neuron receives signals from a sensory organ and transmits the impulse via a dorsal nerve root into the CNS (at the level of spinal cord). The efferent neuron then carries signals from CNS to the effector. The stimulus and response thus forms a reflex arc.

Question 5.
What do you understand by olfactory receptors?
Answer:
The nose contains mucus-coated receptors which are specialized for receiving the sense of smell and are called olfactory receptors. These are made up of olfactory epithelium which consists of three kinds of cells. The neurons of the olfactory epithelium extend from the outside environment directly into a pair of broad bean-sized organs called olfactory bulb. Olfactory bulbs are extensions of the brain’s limbic system.

Long Answer Type Questions

Question 1.
(a) Give an account of spinal nerves in man.
(b) What biological functions are served by the skeletal system?
Answer:
(a) There are 31 pairs of spinal nerve in man. From each segment of the spinal cord, there arises two spinal nerves. Each spinal nerve is a mixed nerve, containing both sensory’ and motor nerve fibres. It runs between the spinal cord and peripheral tissue. The two roots, i. e., motor or ventral and sensory or dorsal connect the spinal nerve to the spinal cord.

The DORSAL ROOT carries sensory or afferent fibre and has dorsal root ganglion at its middle. The VENTRAL, ROOT contains motor or efferent nerve fibers. The dorsal root fibres bring impulses from the peripheral tissue and give rise to sensations like touch, temperature, and pain. The ventral nerve root fibres pass impulses to muscles and glands in the peripheral tissues. The spinal nerve has been named according to their relation with the vertebral column.

These are

  • Eight pairs of cervical,
  • 12 pairs of thoracic,
  • 5 pairs of lumbar,
  • 5 pairs of sacral and
  • a pair of coccygeal or caudal.

(b)

  • The skeletal system forms the rigid structural framework of the body and supports the weight of the body along with its limbs.
  • It affords protection to the internal organs against mechanical injury by forming cage-like compartments, e.g., skull.
  • It serves as a storage depot for calcium and phosphate, which are released for a number of functions of the body.
  • It participates in movement and locomotion.

PSEB 11th Class Biology Important Questions Chapter 22 Chemical Coordination and Integration

Punjab State Board PSEB 11th Class Biology Important Questions Chapter 22 Chemical Coordination and Integration Important Questions and Answers.

PSEB 11th Class Biology Important Questions Chapter 22 Chemical Coordination and Integration

very Short Answer Type Questions

Question 1.
There are many endocrine glands in human body. Name the gland, which is absent in male and the one absent in female. [NCERT Exemplar]
Answer:
The glands, which are absent in male are ovaries and which are absent in female are testes.

Question 2.
Which of the two adrenocortical layers, zona glomerulosa and zona reticularis lies outside enveloping the other?
[NCERT Exemplar]
Answer:
Zona glonierulosa (outer layer) envelopes zona reticularis (inner layer) from the outside.

Question 3.
Name the only hormone secreted by pars intermedia of pituitary gland. [NCERT Exemplar]
Answer:
Melanocyte Stimulating Hormone (MSH).

Question 4.
Mention the name of the largest and the smallest endocrine gland found in man.
Answer:
Thyroid gland is the largest endocrine gland and pituitary gland is the smallest endocrine gland.

Question 5.
A patient complains of constant thirst, excessive passing of urine and low the level blood pressure. When the doctor checked the patient’s blood glucose and blood insulin level, the level were normal or slightly low. The doctor diagnosed the condition as diabetes insipidus. But he decide to measure one more hormone in patient’s blood. Which hormone does the doctor intend to measure? [NCERT Exemplar]
Answer:
Glucagon.

PSEB 11th Class Biology Important Questions Chapter 22 Chemical Coordination and Integration

Question 6.
The outermost layer of adrenal cortex is responsible for secretion of which hormone. Identify?
Answer:
Mineralocorticoids.

Question 7.
Identify the neurohormone that has its functioning in inhibiting the secretion of growth hormone from anterior lobe of pituitary.
Answer:
Somatostatin inhibits the secretion of growth hormone from anterior lobe of pituitary gland.

Question 8.
State the reason for the occurrence of diabetes insipidus in a individual.
Answer:
Deficiency in the secretion of vasopressin (ADH) leads to the disorder known as diabetes insipidus.

Question 9.
Define the term erythropoiesis. Also name the hormone that stimulates it. [NCERT Exemplar]
Answer:
Erythropoiesis is the process of formation of RBCs. The juxtaglomerular cells of kidney produce a peptide hormone called erythropoietin which stimulates it.

Question 10.
What do you understand by the term ANF?
Answer:
Atrial wall of human heart secretes a peptide hormone called atrial natriuretic factor which decreases blood pressure by dilation of the blood vessels.

Question 11.
Mention the name given to the hormones produced by some non-endocrine tissues.
Answer:
Hormones produced by some non-endocrine tissues are called growth factors.

Question 12.
Which two hormones are steroids chemically?
Answer:
Cortisol and testosterone are chemically steroid in nature.

PSEB 11th Class Biology Important Questions Chapter 22 Chemical Coordination and Integration

Short Answer Type Questions

Question 1.
Explain the function of melanin.
Answer:
Melanin controls the circadian variations of the body. During 24 hours different organ system of our body works at different pace. During sleep certain body functions slow down. All of this is known as circadian rhythm. Additionally, melanin influences metabolism, pigmentation, menstruation and defence capability.

Question 2.
How does parathyroid hormone influences calcium uptake in the body?
Answer:
Parathyroid hormone (PTH) increases the Ca2+ levels in the blood. PTH acts on bones and stimulates the process of bone reabsorption (dissolution/demineralization). PTH also stimulates reabsorption of Ca2+ by the renal tubules and increases Ca2+ absorption from the digested food. It is, thus, clear that PTH is a hypercalcemic hormone, i.e., it increases the blood Ca2+ levels. Along with TCT, it plays a significant role in calcium balance in the body.

Question 3.
How do fight or flight hormones prepare our body to fight emergency?
Answer:
Adrenaline and noradrenaline are rapidly secreted in response to stress of any kind and during emergency situations and are called emergency hormones or hormones of fight or flight. These hormones increase alertness, pupillary dilation, piloerection (raising of hairs), sweating etc. Both the hormones increase the heartbeat, the strength of heart contraction, and the rate of respiration. Finally, the body is ready to counter the emergency situations.

Question 4.
What are secondary sexual characters?
Answer:
Characters which do not play direct role in sexual reproduction but are basically means of sexual differentiation are called secondary sexual characters. For example, facial hair and deep voice in males and thin voice in females are secondary sexual characters.

Question 5.
What is acromegaly?
Answer:
Excess secretion of growth hormone in adults, especially in middle age can result in severe disfigurement (especially of the face). This is called acromegaly. This can lead to serious complications and even death; if unchecked. The disease is hard to diagnose in the early stages and is frequently missed for many years, until changes in external features become noticeable.

Long Answer Type Questions

Question 1.
Hypothalamus is a super master endocrine gland. Elaborate. [NCERT Exemplar]
Answer:
Hypothalamus regulates a wide spectrum of body functions. It contains several groups of neurosecretory cells called nuclei, which produce hormones. These hormones regulate the synthesis and secretion of pituitary hormones. However, the hormones produced by hypothalamus are of two types, the releasing hormones (which stimulate secretion of pituitary hormones) and the inhibiting hormones (which inhibit secretions of pituitary hormones).
The hormones reach the pituitary gland through a portal circulatory system and regulate the functions of the anterior pituitary. The posterior pituitary is under the direct regulation of hypothalamus. The oxytocin and vasopressin are the two hormones synthesized by hypothalamus that are transported to posterior pituitary.

Question 2.
A sample of urine was diagnosed to contain high content of glucose and ketone bodies. Based on this observation, answer the following: (NCERT Exemplar)
(i) Which endocrine gland and hormone is related to this condition? %
(ii) Name the cells on which this hormone acts.
(iii) What is the condition called and how can it be rectified?
Answer:
(i) Pancreas gland and insulin hormone is related to this condition.
(ii) The (3-cells of islets of Langerhans of pancreas.
(iii) Prolonged hyperglycemia leads to a complex disorder, called diabetes mellitus, which is associated with loss of glucose through urine and formation of harmful compounds known as ketone bodies. Diabetic patients are successfully treated with insulin therapy.

PSEB 11th Class Biology Important Questions Chapter 22 Chemical Coordination and Integration

Question 3.
(i) Give a diagrammatic representation of the mechanism of protein hormone (e. g., FSH) action.
(ii) Illustrate the differences between the mechanism of action of, a protein and a steroid hormone. [NCERT Exemplar]
Answer:
PSEB 11th Class Biology Important Questions Chapter 22 Chemical Coordination and Integration 1
(ii) Differences between mechanism of action of a protein and a steroid hormone

Protein Hormone Steroid Hormone
Protein hormones interact with membrane-bound receptors. They interact with intracellular receptors.
They generate second messengers (cyclic AMP, IP3, Ca2+, etc.) They regulate gene expression or chromosome function by the interaction of the hormone-receptor complex with the genome.
The second messengers regulate. cellular metabolism. Cumulative biochemical action of hormone-receptor complex results in physiological and developmental effects.

PSEB 11th Class Physics Important Questions Chapter 6 Work, Energy and Power

Punjab State Board PSEB 11th Class Physics Important Questions Chapter 6 Work, Energy and Power Important Questions and Answers.

PSEB 11th Class Physics Important Questions Chapter 6 Work, Energy and Powere

Very short answer type questions

Question 1.
Under what condition is the work done by a force inspite of displacement being taking place?
Answer:
Work done by a force is zero inspite of displacement being taking place, if displacement is in a direction perpendicular to that of force applied.

Question 2.
Can acceleration be produced without doing any work? Give example.
Answer:
Yes, for uniform circular motion, no work done but a centripetal acceleration is present.

Question 3.
Does the amount of work done depend upon the fact that how fast is a load raised or moved in the direction of force?
Answer:
The amount of work does not depend upon the fact that how fast is a load raised or moved in the direction of force.

PSEB 11th Class Physics Important Questions Chapter 6 Work, Energy and Power

Question 4.
A body is moving along a circular path. How much work is done by the centripetal force?
Answer:
For a body moving along a circular path, the centripetal force acts along the radius while the displacement is tangential, i. e., θ = 90 °, therefore,
W = Fscos90° = 0.

Question 5.
What is the source of kinetic energy of the bulelt coming out of a rifle?
Answer:
The source of kinetic energy of bullet is the potential energy of the compressed spring in the loaded rifle.

Question 6.
A spring is cut into two equal halves. How is the spring constant of each half affected?
Answer:
Spring constant of each half becomes twice the spring constant of the original spring.

Question 7.
Is collision between two particles possible even without any physical contact between them?
Answer:
Yes, in atomic and subatomic particles collision without any physical contact between the colliding particles is taking place e. g., Rutherford’s alpha particles scattering.

Question 8.
Why is electrical power required at all when the elevator is descending? Why should there be a limit on the number of passengers in this case? (NCERT Exemplar)
Answer:
When the elevator is descending, then electric power is required to prevent it from falling freely under gravity.
Also, as the weight inside the elevator increases, its speed of descending – increases, therefore, there should be a limit on the number of passengers in the elevator to prevent the elevator from descending with large velocity.

PSEB 11th Class Physics Important Questions Chapter 6 Work, Energy and Power

Short answer type questions

Question 1.
A block of mass M is pulled along a horizontal surface by applying a force at an angle θ with horizontal. Coefficient of friction between block and surface is μ. If the block travels with uniform velocity, find the work done by this applied force during a displacement d of the block.
PSEB 11th Class Physics Important Questions Chapter 6 Work, Energy and Power 1
Solution:
The forces acting on the block are shown in figure. As the block moves with uniform velocity the forces add up to zero.
∴ Fcosθ = μN ………….. (i)
Fsinθ + N = Mg ……………. (ii)
Eliminating N from equations (i) and (ii)
F cosθ = μ(Mg – F sinθ)
F = [Latex]\frac{\mu M g}{\cos \theta+\mu \sin \theta}[/Latex]
Work done by this force during a displacement d
W = F. d cosθ = [Latex]\frac{\mu M g d \cos \theta}{\cos \theta+\mu \sin \theta}[/Latex]

Question 2.
Two springs have force constants K2 and K2 (K1 > K2 )• On which spring is more work done when they are stretched by the same force?
Solution:
PSEB 11th Class Physics Important Questions Chapter 6 Work, Energy and Power 2
As x1 < x2
∴ W1 < W2 or W2 > W1

Question 3.
A particle is moving in a circular path of radius r with constant speed. Due to change in the direction of motion of the particle continuously, the velocity of the particle is changing. But the kinetic energy of the particle remains the same. Explain why ?
Solution:
Kinetic energy is given by
E = \(\frac{1}{2}\) mυ2 = \(\frac{1}{2}\) m(\(\vec{v} \cdot \vec{v}\))
Since \(\vec{v} \cdot \vec{v}\) – υ2, a scalar quantity, so it is the speed which is taken into account while calculating the kinetic energy of the particle. As the speed is constant, so kinetic energy of the particle will also remain constant.

PSEB 11th Class Physics Important Questions Chapter 6 Work, Energy and Power

Question 4.
Can a body have energy without momentum? If yes, then explain how they are related with each other?
Solution:
Yes, when p = 0,
Then, K = \(\frac{p^{2}}{2 m}\) = 0
But E = K + U = U (potential energy), which may or may not be zero.

Question 5.
Two bodies A and B having masses mA and mB respectively have equal kinetic energies. If pA and pB are their respective momenta, then prove that the ratio of momenta is equal to the square root of ratio of respective masses.
Solution:
Let υA and υB be the velocities of A and B respectively.
Since their kinetic energies are equal,
PSEB 11th Class Physics Important Questions Chapter 6 Work, Energy and Power 3

Question 6.
Two ball bearings of mass m each, moving in opposite directions with equal speed υ, collide head on with each other. Predict the outcome of the collision, assuming it to be perfectly elastic.
Solution:
Here, m1 = m2 = m
u1 = υ,u2 = -υ
Velocities of two balls after perfectly elastic collision between them are
PSEB 11th Class Physics Important Questions Chapter 6 Work, Energy and Power 4
After collision, the two ball bearings will move with same speeds, but their direction of motion will be reversed.

PSEB 11th Class Physics Important Questions Chapter 6 Work, Energy and Power

Question 7.
An engine is attached to a wagon through a shock absorber of length 1.5 m. The system with a total mass of 50,000 kg is moving with a speed of 36 kmh-1 when the brakes are applied to bring it to rest. In the process of the system being brought to rest, the spring of the shock absorber gets compressed by 1.0 m. If 90% of
energy of the wagon is lost due to friction, calculate the spring constant. (NCERT Exemplar)
Solution:
Given, mass of the system (m) = 50,000 kg
Speed of the system (υ) = 36 km/h
= \(\frac{36 \times 1000}{60 \times 60}\) = 10 m/s
Compression of the spring (x) = 1.0 m
KE of the system = \(\frac{1}{2}\) mυ2 = \(\frac{1}{2}\) × 50000 × (10)2
= 25000 × 100 J = 2.5 × 106J
Since, 90% of KE qf the system is lost due to friction, therefore, energy transferred to shock absorber, is given by
ΔE = \(\frac{1}{2}\)kx2 = 10% of total KE of the system
= \(\frac{10}{100}\) × 2.5 × 106 J or k = \(\frac{2 \times 2.5 \times 10^{6}}{10 \times(1)^{2}}\)
= 5.0 × 106 N/m

Question 8.
An adult weighting 600 N raises the centre of gravity of his body by 0.25 m while taking each step of 1 m length in jogging. If he jogs for 6 km, calculate the energy utilised by him is jogging assuming that there is no energy loss due to friction of ground and air. Assuming that the body of the adult is capable of converting 10% of energy intake in the form of food, calculate the energy equivalents of food that would be required to compensate energy utilised for jogging. (NCERT Exemplar)
Solution:
Given, weight of the adult (w) = mg = 600 N
Height of each step = h = 0.25m
Length of each step = 1 m
Total distance travelled = 6 km = 6000 m
∴ Total number of steps = \(\frac{6000}{1}\) = 6000
Total energy utilised in jogging = n × mgh
= 6000 × 600 × 0.25J = 9 × 105 J
Since, 10% of intake energy is utilised in jogging.
∴ Total intake energy = 10 × 9 × 105J = 9 × 106J

PSEB 11th Class Physics Important Questions Chapter 6 Work, Energy and Power

Long answer type questions

Question 1.
A body of mass 0.3 kg is taken up an inclined plane length 10 m and height 5 m, and then allowed to slide down the bottom again. The coefficient of friction between the body and the plane is 0.15. What is the
(i) work done by gravitational force over the round trip?
(ii) work done by the applied force over the upward journey?
(iii) work done by the frictional force over the round trip?
(iv) kinetic energy of the body at the end of trip? (Take g = 10 ms-2)
PSEB 11th Class Physics Important Questions Chapter 6 Work, Energy and Power 5
Solution:
Upward journey
PSEB 11th Class Physics Important Questions Chapter 6 Work, Energy and Power 6
Let us calculate work done by different forces over upward joume Work done by gravitational force
Wi = (mg sinθ)s cos 180°
W 1= 0.3 × 10 sin30° × 10 (-1)
W1 =-15J
Work donp by force of friction
W2 = (μ mg cosθ)s cos180°
W2 = 0.15 × 0.3 × 10 cos30° × 10 (-1)
W2 =-3.879 J
Work done by external force
W3 = Fext × s × cos0°
W3 = [mg sinθ + μ mg cosθ] × 10 × 1
W3 = 18.897 J

Downward journey
PSEB 11th Class Physics Important Questions Chapter 6 Work, Energy and Power 7
mg sin30°> μ mg cos30°
Work done by the gravitational force
W4 = mg sin 30° × scos0°
W4 = 0.3 × 10 × \(\frac{1}{2}\) × 10 = +15J
Work done by the frictional force
W5 = μmg cos30° × s cos180°
= 0.15 × 0.3 × \(\frac{10 \sqrt{3}}{2}\) × 10 × (-1) = – 3.897 J
(i) Work done by gravitational force over the round trip
= W1 + W4 = 0J
(ii) Work done by applied force over upward journey
= W3 = 18.897J
(iii) Work done by frictional force over the round trip
W2 + W5 = – 3.897 + (-3.897) = – 7.794 J
(iv) Kinetic energy of the body at the end of the trip
W4 + W5 = 11.103 J

PSEB 11th Class Physics Important Questions Chapter 6 Work, Energy and Power

Question 2.
Prove that when a particle suffers an oblique elastic collision with another particle of equal mass anil initially at rest, the two particles would move in mutually perpendicular directions after collisions.
Solution:
Let a particle A of mass m and having velocity u collides with particle B of equal mass but at rest. Let the collision be oblique elastic collision and after collision the particles A and B move with velocities υ1 and υ2 respectively inclined at an angle 0 from each other.
PSEB 11th Class Physics Important Questions Chapter 6 Work, Energy and Power 8
Applying principle of conservation of linear momentum, we get
mu = mυ1 +mυ2 or u = υ1+ υ2
or u2 = (υ1 + υ2) – (υ1 + υ2)
= υ12 + υ22 + 2υ1υ2cos0 ………….. (i)
Again as total KE before collision = Total KE after collision
∴ \(\frac{1}{2}\) mu2 = \(\frac{1}{2}\)mυ12 + \(\frac{1}{2}\)mυ22
⇒ u2 = υ12 + υ22 ……………. (ii)
Comparing eqs. (i) and (ii), we get 2υ1υ2 cosθ = 0
As in an oblique collision both υ1 and υ2 are finite, hence cos0 = 0
⇒ θ = cos-1(0) = \(\frac{\pi}{2}\)
Thus, particles A and B are moving in mutually perpendicular directions after the collision.

PSEB 11th Class Biology Important Questions Chapter 4 Animal Kingdom

Punjab State Board PSEB 11th Class Biology Important Questions Chapter 4 Animal Kingdom Important Questions and Answers.

PSEB 11th Class Biology Important Questions Chapter 4 Animal Kingdom

Very short answer type questions

Question 1.
What are coelomates? Give two examples.
Answer:
Animals possessing coelom are called coelomates, e.g., Annelids, molluscs, arthropods, etc.

Question 2.
Body cavity is the cavity present between body wall and gut wall. In some animals the body cavity is not lined by mesoderm. Such animals are called: [NCERT Exemplar]
Answer:
Pseudocoelomates.

PSEB 11th Class Biology Important Questions Chapter 4 Animal Kingdom

Question 3.
In some animal groups, the body is found to be divided into compartments with atleast some organs/organ repeated. Name this characteristic feature. [NCERT Exemplar]
Answer:
The segmentation that simultaneously divides body both externally and internally is called metamerism.

Question 4.
Name the group which lack digestive tract.
Answer:
Porifera.

Question 5.
Name an animal having canal system and spicules. [NCERT Exemplar]
Answer:
Scypha (sycon)/Leucosolenia.

Question 6.
Give an example of animal which exhibit alternation of generation. [NCERT Exemplar]
Answer:
Obelia, shows alternation of asexual and sexual phases.

Question 7.
Name the animal which exhibits the phenomenon of bioluminescence. Mention the phylum to which it belongs.
[NCERT Exemplar]
Answer:
Pleurobrachia, phylum – Ctenophora.

PSEB 11th Class Biology Important Questions Chapter 4 Animal Kingdom

Question 8.
How is mesoglea different in ctenophores that in cnidarians?
Answer:
The mesoglea in ctenophores also contains amoebocytes, elastic fibres and muscle cells.

Question 9.
What is the role of radula in Mollusca? [NCERT Exemplar]
Answer:
It is the rasping organ that help in feeding.

Question 10.
Identify the animal in which adults exhibit radial symmetry and larvae exhibit bilateral symmetry. [NCERT Exemplar]
Answer:
In Echinodermata, the adults are radially symmetrical and larvae are bilaterally symmetrical.

Question 11.
Why are urochordates called tunicates?
Answer:
This is because the soft body of urochordates is surrounded by a thick test or tunic, often transparent or translucent.

Question 12.
In which fishes cartilaginous skeleton is present?
Answer:
Chondrichthyes.

PSEB 11th Class Biology Important Questions Chapter 4 Animal Kingdom

Question 13.
Which amphibians show branchial (gills) respiration?
Answer:
Young ones of most of the amphibians which are aquatic show branchial respiration.

Question 14.
What is the importance of pneumatic bones and air sacs in Aves? [NCERT Exemplar]
Answer:

  • Pneumatic bones are light but strong, the feature which helps in flight,
  • Air sacs increase the efficiency of respiration and provide buoyancy to the animal.

Short answer type questions

Question 1.
Define tissue level of organization in the Kingdom Animalia. Give some examples of organisms showing tissue level of organization.
Answer:
In tissue level of organization there are specified groups of cells to carry out specific functions. This is a start of division of labour in the Animal Kingdom. Examples: Aurelia and Hydra.

Question 2.
What are diploblastic and triploblastic organisation?
Answer:
Animals in which the cells are arranged in two embryonic layers, an external ectoderm and an internal endoderm, are called diploblastic animals, e.g., coelenterates. An undifferentiated layer, mesoglea, is present in between the ectoderm and the endoderm. Those animals in which the developing embryo has a third germinal layer, mesoderm, in between the ectoderm and endoderm, are called triploblasdc animals (platyhelminthes to chordates).

Question 3.
Write two characters on the basis of which you can say that Coelenterata is more evolved than Porifera.
Answer:
(a) Porifera shows cellular level of organization, while Coelenterata shows tissue level of organisation.
(b) All members of Porifera are sessile, i.e., they are attached to the substratum, while some members of Coelenterata are motile, showing further improvement.

PSEB 11th Class Biology Important Questions Chapter 4 Animal Kingdom

Question 4.
On the basis of which characters you can say that Aschelminthes are more advanced compared to Platyhelminthes?
Answer:
(a) Platyhelminthes are acoelomate,while Aschelminthes are pseudocoelomates. This indicates development of mesoderm.
(b)In Platyhelminthes both sexes are on the same animal, while in Aschelminthes there is segregation of sexes. This shows another point of evolution.

Question 5.
Give a description of the water vascular system in Echinodermata..
Answer:
Water Vascular System in Echinodermata: The water vascular system is a hydraulic system used by echinoderms, such as starfish and sea urchins, for locomotion, food and waste transportation, and respiration. The system is composed of canals connecting numerous tube feet. Echinoderms move by alternately contracting muscles that force water into the tube feet, causing them to extend and push against the ground, then relaxing to allow the feet to retract.

Long answer type questions

Question 1.
Differentiate between polyp and medusa. [NCERT Exemplar]
Answer:
Differences between polyp and medusa are as follows :

Polyp Medusa
1. It is a fixed zooid. It is free swimming.
2. It is asexual. It is sexual.
3. It is cylindrical in outline. Medusa is umbrella-shaped.
4. Tentacles found at upper end of manubrium. Tentacles occur along the margin of umbrella.
5. Mouth is circular and terminal over upright manubrium. Mouth is four sided, lies at the lower end of hanging manubrium.
6. Velum and sense organs are absent. Medusa have a-circular velum and eight sense organs or statocysts.

Question 2.
Differentiate between Chordates and Non-Chordates.
Answer:
Differences between chordates and non-chordates are given below:

Chordates Non-Chordates
•» Notocord is present at stages in some stages of development. Notochord is absent.
•» Central nervous system is dorsal, hollow, single and non-ganglionated. Central nervous system is ventral, solid, double and ganglionated.
•» Gill slits present on lateral side of pharynx in sum stages of throughout life. Gill slits are absent.
•» Tail is present in some stages and throughout life. Tail generally absent.
•» Heart is ventral. Heart is dorsal.
•» Haemoglobin is present in RBCs. It is present in plasma.

PSEB 11th Class Biology Important Questions Chapter 4 Animal Kingdom

Question 3.
Which features make mammals as most successful and dominant animals?
Answer:
Features which make mammals as dominant and successful animals are as follows:

  • The presence of an insulating and protective hairy exoskeleton
  • They are warm blooded so have high rate of metabolism.
  • They are viviparous animals and show placentation and intrauterine development which increases the chances for survival of young ones.
  • They show high degree of parental care.
  • They have more developed hearing efficiency due to the presence of pinna, three ear-ossicles and coiled cochlea in the ear.
  • They are able to speak through language.
  • They have good power of learning due to the presence of more developed brain.

PSEB 11th Class Biology Important Questions Chapter 3 Plant Kingdom

Punjab State Board PSEB 11th Class Biology Important Questions Chapter 3 Plant Kingdom Important Questions and Answers.

PSEB 11th Class Biology Important Questions Chapter 3 Plant Kingdom

Very short answer type questions

Question 1.
Name the types of classification of plants.
Answer:
Artificial, natural and phylogenetic.

Question 2.
Which system indicates evolutionary as well as genetic relationships among organisms?
Answer:
Phylogenetic system of classification.

Question 3.
What is cytotaxonomy?
Answer:
Cytotaxonomy is a method of classification. It is based on cytological structure and their relatedness.

PSEB 11th Class Biology Important Questions Chapter 3 Plant Kingdom

Question 4.
Food is stored as floridean starch in Rhodophyceae. Mannitol is the reserve food material of which group of algae?
[NCERT Exemplar]
Answer:
Phaeophyceae.

Question 5.
Holdfast, stipe and frond constitutes the plant body in case of
[NCERT Exemplar]
(a) Rhodophyceae
(b) Chlorophyceae
(c) Phaeophyceae
(d) All of these
Answer:
The lamina of Phaeophyceae members large sized body with differentiation of holdfast, stipe and lamina.

Question 6.
The plant body in higher plants is well differentiated and well developed. Roots are the organs used for the purpose of absorptions. What is the equivalent of the roots in the less developed lower plants? [NCERT Exemplar]
Answer:
Rhizoids.

Question 7.
Most algal genera show haplontic life cycle. Name an alga which is (i) Haplodiplontic (ii) Diplontic [NCERT Exemplar]
Answer:
Haplodiplontic: Ulva, Dictyota.
Diplontic: Fucus, Cladophora, Glomerata.

Question 8.
How are mosses considered ecologically important?
Answer:
Mosses, along with lichens are the first organism to colonise rocks, hence are ecologically important.

PSEB 11th Class Biology Important Questions Chapter 3 Plant Kingdom

Question 9.
A prothallus is
(a) a structure in pteridophyte formed before the thallus develops
(b) a sporophytic free-living structure formed in pteridophyte
(c) a gametophytic free-living structure formed in pteridophytes
(d) a primitive structure formed after fertilisation in pteridophyte
[NCERT Exemplar]
Answer:
Gametophyte is a free-living small thalloid structure called prothallus. In most ferns, the prothallus is green and autotrophic.

Question 10.
Where are seeds located in gymnosperm?
Answer:
Seeds lie naked or exposed on the surface of megasporophyll.

Question 11.
The embryo sac of an angiosperm is made up of:
(i) 8 cells
(ii) 7 cells and 8 nuclei
(iii) 8 nuclei
(iv) 7 cells and 7 nuclei [NCERT Exemplar]
Answer:
(ii) Embryo sac of angiosperm develops up to 8 nucleate state prior to fertilisation. There is a three celled egg apparatus, three antipodal cells and two polar nuclei.

Question 12.
What is alternation of generations?
Answer:
Alernation of generations is regular switch over from gamete bearing haploid gametophyte to haploid spore producing diploid sporophyte.

PSEB 11th Class Biology Important Questions Chapter 3 Plant Kingdom

Short answer type questions

Question 1.
What are the main differences among Chlorophyceae, Phaeophyceae and Rhodophyceae?
Answer:
PSEB 11th Class Biology Important Questions Chapter 3 Plant Kingdom 1
PSEB 11th Class Biology Important Questions Chapter 3 Plant Kingdom 2

Question 2.
What is the general structure of bryophytes?
Answer:
Structure of Bryophytes: It is thallus-like and prostrate or erect, and attached to the substratum by unicellular or multicellular rhizoids. They lack true roots, stem or leaves. They may possess root-like, or stem-like structures.

Question 3.
What is the general structure of pteridophytes?
Answer:

  • The main plant body is a sporophyte which is differentiated into true root, stem and leaves. These organs possess well-differentiated vascular tissues.
  • The leaves in pteridophyta are small (microphylls) as in Selaginella or large (macrophylls) as in ferns.
  • The sporophytes bear sporangia that are subtended by leaf-like appendages called sporophylls. In some cases sporophylls may form distinct compact structures called strobili or cones (Selaginella, Equisetum).

PSEB 11th Class Biology Important Questions Chapter 3 Plant Kingdom

Question 4.
Write short notes on:
(a) Importance of carbon fixation by algae.
(b) Importance of Gymnosperms
(c) Importance of Angiosperms
(d) Medicinal use of algae
Answer:
(a) About 50% of carbon fixation is done by algae. This enables majority of sea organisms to get the required food.
(b) Gymnosperms are mainly used as decorative plants. Certain paints are
prepared from Gymnosperm plants.
(c) Angiosperms are the major providers of food-grains to the mankind.
(d) Spirullina is made by algae and is used as a nutritional supplement.

Long answer type questions

Question 1.
Algae are known to reproduce asexually by a variety of spores under different environmental condition. Name these spores and the conditions under which they are produced. [NCERT Exemplar]
Answer:
Zoospores: Flagellate spores, under favourable conditions.
Aplanospores: Non-flagellate, thin-walled spores under approaching unfavourable conditions.
Hypnospores: Thick-walled, resting spores in unfavourable conditions.
Akinetes: Thin-walled and thick-walled spores formed from whole cells in unfavourable conditions. .
Autospores: Spores which look exactly like parent cell formed under favourable conditions.

Question 2.
Write about habit and habitat of algae.
Answer:
Habit and Habitat of Algae: Algae are chlorophyll-bearing, simple, thalloid, autotrophic and largely aquatic (both fresh water and marine) organisms. They occur in a variety of other habitats : moist stones, soils and wood. Some of them also occur in association with fungi (lichen) and animals (e.g., on sloth bear).

PSEB 11th Class Biology Important Questions Chapter 3 Plant Kingdom

Question 3.
What are the differences betweenpinus and cycas?
Answer:

Pinus Cycas
1. Roots are micorrhizal. 1. Roots are not micorrhizal.
2. Stems are branched. 2. Stems are unbranched.
3. Male and female strobili are on same tree. 3. They are on different trees.

PSEB 11th Class Biology Important Questions Chapter 20 Locomotion and Movement

Punjab State Board PSEB 11th Class Biology Important Questions Chapter 20 Locomotion and Movement Important Questions and Answers.

PSEB 11th Class Biology Important Questions Chapter 20 Locomotion and Movement

Very short answer type questions

Question 1.
Give the name of the cells/tissues in human body which:
(i) exhibit amoeboid movement.
(ii) exhibit ciliary movement. [NCERT Exemplar]
Answer:
(i) Macrophages,
(ii) Ciliated, epithelium of trachea.

Question 2.
Which property of muscles is used effectively in muscular movement?
Answer:
Contractile property of muscles.

Question 3.
Give the name of the oxygen-carrying pigment present in skeletal muscle.
Answer:
Myoglobin or muscle hemoglobin.

PSEB 11th Class Biology Important Questions Chapter 20 Locomotion and Movement

Question 4.
Label the different components of actin filament in the diagram given below: [NCERT Exemplar]
Answer:
PSEB 11th Class Biology important Questions Chapter 20 Locomotion and Movement 1

Question 5.
What causes muscle fatigue?
Answer:
Accumulation of lactic acid.

Question 6.
The three tiny bones present in middle ear are called ear ossicles. Write them in correct sequence beginning from eardrum. [NCERT Exemplar]
Answer:
Malleus, incus and stapes.

Question 7.
What is the difference between the matrix of bone and cartilage? [NCERT Exemplar]
Answer:
The matrix of bone is hard due to calcium salts, whereas, the cartilage has slightly pliable matrix due to chondroitin salts.

Question 8.
How many total bones are there in human body? Name the largest and strongest bone.
Answer:
Human body contains 206 bones. Femur is the largest and strongest bone of human body.

Question 9.
Give the name of the cavity in the girdle to which head of femur articulates.
Answer:
Acetabulum.

Question 10.
Give the name of the funny bone.
Answer:
Olecranon process on top of the ulna is called the funny bone.

PSEB 11th Class Biology Important Questions Chapter 20 Locomotion and Movement

Question 11.
Give the location of ball and socket joint in a human body. [NCERT Exemplar]
Answer:
Shoulder joint (between pectoral girdle and head of humerus).

Question 12.
What substance is responsible for lubricating the freely movable joint at the shoulder? ,
Answer:
Synovial fluid.

Short answer type questions

Question 1.
Explain anaerobic breakdown of glycogen in muscles and its effect.
Answer:
Anaerobic Breakdown of Glycogen: The reaction time of the fibres can vary in different muscles. Repeated activation of the muscles can lead to the accumulation of lactic acid due to anaerobic breakdown of glycogen in them, causing fatigue.

Question 2.
Describe the structure of the human skull.
Answer:

  • The skull is composed of two sets of bones-cranial and facial, that totals to 22 bones.
  • Cranial bones are 8 in number. They form the hard protective outer covering, cranium for the brain.
  • The facial region is made up of 14 skeletal elements which form thefront part of the skull.
  • A single U-shaped bone called hyoid is present at the base of the buccal cavity and it is also included in the skull.
  • Each middle ear contains three tiny bones-Malleus, Incus and Stapes, collectively called Ear Ossicles.
  • The skull region articulates with the superior region of the vertebral column with the help of two occipital condyles (dicondylic skull).

Question 3.
Explain the structure of the vertebral column of human.
Answer:
Vertebral Column: Our vertebral column is formed by 26 serially arranged units called vertebrae and is dorsally placed. It extends from the base of the skull and constitutes the main framework of the trunk. Each vertebra has a central hollow portion (neural canal) through which the spinal cord passes.
First vertebra is the atlas and it articulates with the occipital condyles.

The vertebral column is differentiated into following regions starting from the skull:

  1. cervical (7),
  2. thoracic (12),
  3. lumbar (5),
  4. sacral (1-fused) and
  5. coccygeal (1-fused) regions

The number of cervical vertebrae are seven in almost all mammals including human beings. The vertebral column protects the spinal cord, supports the head and serves as the point of attachment for the ribs and musculature of the back. Sternum is a flat bone on the ventral midline of thorax.

PSEB 11th Class Biology Important Questions Chapter 20 Locomotion and Movement

Question 4.
Describe the structure of the rib cage of human.
Answer:
Rib Cage: There are 12 pairs of ribs. Each rib is a thin flat bone connected dorsally to the vertebral column and ventrally to the sternum. It has two articulation surfaces on its dorsal end and is hence called bicephalic.
First seven pairs of ribs are called true ribs. Dorsally, they are attached to the thoracic vertebrae and ventrally connected to the sternum with the help of hyaline cartilage.

The 8th, 9th and 10th pairs of ribs do not articulate directly with the sternum but join the seventh rib with the help of hyaline cartilage. These are called verte brochondral (false) ribs. Last 2 pairs (11th and 12th) of ribs are not connected ventrally and are, therefore, called floating ribs. Thoracic vertebrae, ribs and sternum together form the rib cage.

Question 5.
Give a description of the appendicular skeleton in human.
Answer:
Appendicular Skeleton: The bones of the limbs alongwith their girdles constitute the appendicular skeleton. Each limb is made of 30 bones.

Bones of Limbs
Fore’ Limb Hind Limb
Humerus, Femur,
Radius, Tibia,
Ulna Fibula,
Carpals (8) Tarsals (7)
Metacarpals (5) Metatarsals (5)
Phalanges (14) Phalanges (14)
Patella

Question 6.
Write a short note on disorders of muscular and skeletal systems.
Answer:
Disorders of Muscular System

  • Myasthenia gravis: It is an auto-immune disorder, affecting the neuromuscular junction leading to progressive weakening and paralysis of skeletal muscles.
  • Muscular dystrophy: It is a genetic disorder resulting in progressive degeneration of skeletal muscles.
  • Tetany: It refers to the continued state of contraction or wild contractions of muscles due to low Ca++ in body fluids.

Disorders of Skeletal System:

  • Arthritis: Inflammation of joints.
  • Osteoporosis: Age-related disorder characterized by decreased bone mass and increased chances of fractures. Decreased levels of estrogen is a common cause.
  • Gout: Inflammation of joints due to accumulation of uric acid crystals.

Long answer type questions

Question 1.
Give answer for the following:
(i) Female pelvis is larger and has a broader front than male pelvis. Why?
(ii) Name the different curves of vertebral column.
(iii) What is a sesamoid bone? Name it.
(iv) Which bones have become modified to form ear ossicles?
Answer:
(i) Female pelvis is larger and has a broader front. This is an adaptation for childbirth.
(ii) Vertebral column forms four curves, i.e., cervical, thoracic, lumbar, and sacral located in the neck, thorax, abdomen, and pelvis respectively.
(iii) A bone embedded within a tendon is called a sesamoid bone, e.g., Patella which covers the knee ventrally.
(iv) Articular bone of lower jaw modifies to be malleus. Quadrate bone of upper jaw becomes incus and hyomandibular gets modified to become stapes.

PSEB 11th Class Biology Important Questions Chapter 2 Biological Classification

Punjab State Board PSEB 11th Class Biology Important Questions Chapter 2 Biological Classification Important Questions and Answers.

PSEB 11th Class Biology Important Questions Chapter 2 Biological Classification

Very short answer type questions

Question 1.
Name the organisms living in salty areas. [NCERT Exemplar]
Answer:
Halophiles live in habitats having high salinity and high light intensity.

Question 2.
Name the kingdom under which cyanobacteria have been classified.
Answer:
Cyanobacteria are prokaryotic organisms belong to kingdom – Monera.

PSEB 11th Class Biology Important Questions Chapter 2 Biological Classification

Question 3.
What is the principle underlying the use of cyanobacteria in agricultural fields for crop improvement? [NCERT Exemplar]
Answer:
Some cyanobacteria live in mutually beneficial relationship with plants, obtaining food and shelter and fixing nitrogen for the plant. They also reduce soil alkalinity and improve soil texture.

Question 4.
Are chemosynthetic bacteria autotrophic or heterotrophic? [IMCERT Exemplar]
Answer:
Chemosynthetic bacteria are- autotrophs because they are able to synthesize their food from inorganic raw material with the help of energy obtained from chemical reaction.

Question 5.
Fusion of two gametes which are dissimilar in size is termed as. [NCERT Exemplar]
Answer:
Anisogamy, it occurs in Ceratium a dinoflagellate.

Question 6.
Why are cysts formed in protistans?
Answer:
Cysts formation helps to over come unfavourable condition.

PSEB 11th Class Biology Important Questions Chapter 2 Biological Classification

Question 7.
What kind of nutrition occurs in a parasite?
Answer:
Parasites have phagotrophic and absorptive type of nutrition.

Question 8.
An association between roots of higher plants and fungi is called.
Answer:
Mycorrhiza is a symbiotic association between a fungus and the root of a plant. Mycorrhiza does not penetrate deep but remains in the superficial layers of the soil.

Question 9.
How the saprotrophic Basidiomycetes are able to decompose plant matter?
Answer:
The saprotrophic Basidiomycetes can decompose plant matter because they have enzymes for metabolising both cellulose and lignin.

Question 10.
Which are the most advanced group of fungi?
Answer:
Basidiomycetes.

Question 11.
What is capsid and how it is useful for viruses?
Answer:
Capsid is a proteinaceous covering around the virus. It protects the nucleoid from damage from physical and chemical agents.

PSEB 11th Class Biology Important Questions Chapter 2 Biological Classification

Question 12.
Which enzyme is present in bacteriophages?
Answer:
Lysozyme is present in the region that comes in contact with host cell.

Short answer type questions

Question 1.
Write five beneficial usage or effects of bacteria.
Answer:
(a) Curdling of milk
(b) Lactobacillus is an important commensal in the gut flora of humans.
(c) Penicillin antibiotics are prepared by bacteria.
(d) Bacteria is a good decomposer, so it assists in completing the energy cycle.
(e) Rhizobium bacteria helps in nitrogen fixation.

Question 2.
What is the role of methanogens?
Answer:
Methanogens are a type of bacteria which live in the gut of ruminating animals. They assist those animals in digestion and the byproduct of that digestive process is methane. More number of livestock population results in increased methane level in the environment leading to global warming. So, indirectly methanogens can be responsible for global warming.

Question 3.
Cyanobacteria plays a major role in our ecology. Discuss.
Answer:
Cyanobacteria, also known as ‘blue-green algae’ help in carbon fixation in a major way on the ocean surface. They are helpful in nitrogen fixation in paddy fields leading to a better harvest. About 80% of photosynthesis on ocean surface is done by cyanobacteria. So, it can be said that they play a major role in our ecology.

Question 4.
Give a diagrammatic representation of classification of Protista.
Answer:
PSEB 11th Class Biology Important Questions Chapter 2 Biological Classification 1

PSEB 11th Class Biology Important Questions Chapter 2 Biological Classification

Long answer type questions

Question 1.
Answer the following:
(i) A poisonous mushroom having white spores
(ii) Edible Basidiomycetes
(iii) Used in brewing industry
(iv) It is searched by trained pets
(v) Root like, cards like hyphal masses having a distinct growing point.
(vi) Non-motile meiospores develop in Basidiomycetes
(vii) Compact groups of hyphal produced to overcome unfavourable conditions.
Answer:
(i) toadstools
(ii) mushrooms and young pufballs
(iii) brewer’s yeast Saccharomyces cerevisiae
(iv) Truffles (tuber like underground fungus)
(v) Rhizomorphs perennate during periods of scarcity of food and water.
(vi) Basidiospores (develop exogenously)
(vii) Sclerotia under favourable conditions each one forms a new mycelium.

PSEB 11th Class Biology Important Questions Chapter 1 The Living World

Punjab State Board PSEB 11th Class Biology Important Questions Chapter 1 The Living World Important Questions and Answers.

PSEB 11th Class Biology Important Questions Chapter 1 The Living World

Very short answer type questions

Question 1.
Define living things.
Answer:
The organisms exhibiting growth, development, metabolism, response to stimuli, reproduction and other characteristics such as movement, etc., are called living things.

Question 2.
In which organisms reproduction is synonymous with growth?
Answer:
In unicellular organisms like Amoeba, bacteria and unicellular algae, reproduction is synonymous with growth, i. e., increase in number of cells.

PSEB 11th Class Biology Important Questions Chapter 1 The Living World

Question 3.
Amoeba multiplies by mitotic cell division. Is this phenomenon growth or reproduction? Explain. [NCERT Exemplar]
Answer:
The phenomenon is reproduction in which unicellular organisms like Amoeba, cell division is a means of multiplication, while in multicellular organisms, it is a means of growth.

Question 4.
Can we relate metabolism with growth of the body?
Answer:
Metabolism occurs due to two phenomena, i.e., anabolism and catabolism. While growth of living things occur when quantity of anabolic reactions exceeds quantity of catabolic reactions.

Question 5.
Linnaeus is considered as father of taxonomy. Name two other botanists known for their contribution to the field of taxonomy. [NCERT Exemplar]
Answer:
John Ray and Bentham and Hooker.

Question 6.
What does ICZN stand for? [NCERT Exemplar]
Answer:
ICZN: International Code of Zoological Nomenclature

PSEB 11th Class Biology Important Questions Chapter 1 The Living World

Question 7.
How is diversity in living world related to taxonomy?
Answer:
The spectrum of diversity in the living world can be known only through the study of taxonomy.

Question 8.
Which is the largest botanical garden in the world? Name a few well known botanical gardens in India. [NCERT Exemplar]
Answer:
Largest botanical garden in the world is Royal Botanical Garden, Kew
(London). Some well known botanical gardens in India are as follows:

  • National Botanical Garden, Lucknow
  • Lloyed Botanical Garden, Darjeeling
  • Indian Botanical Garden Sibpur, Kolkata

Question 9.
The concept of new systematics was developed by which scientist?
Answer:
Julian Huxley (1940)

Question 10.
How correlated characters help in defining genus?
Answer:
Correlated characters are those common features, which are used in delimitation of a taxon above the rank of species.

Short answer type questions

Question 1.
What do you know about herbarium?
Answer:
Herbarium is a store house of collected plant specimens that are dried, pressed and preserved on sheets. Further, these sheets are arranged according to k universally accepted system of classification. These specimens, along with their descriptions on herbarium sheets, become a store house or repository for future use. The herbarium sheets also carry a label providing information about date and place of collection, English, local and botanical names, family, collector’s name, etc. Herbaria also serve as quick referral systems in taxonomical studies.

PSEB 11th Class Biology Important Questions Chapter 1 The Living World

Question 2.
How is botanical garden useful for scientists?
Answer:
In a botanical garden various plant species are reared. Special artificial climate is created for a plant’s specific needs. The purpose of botanical garden is to maintain a rich flora of diverse species. Since, they are live specimens so they help scientists in studying physiology and anatomy over a long duration. Imagine if Mendel were given a botanical garden full of variety of species. He could have done experiment on so many plants and may have come with more insights.

Question 3.
Write a short note on museum.
Answer:
Museums are those places which have collections of preserved animals and plants for taxonomic studies. The organisms are exhibited in the following manners:

  • The plant and animal specimens are kept in chemical solutions and are preserved for longer duration.
  • Plant and animal specimens may also be preserved as dry specimens.
  • Insects are preserved in insect boxes; the collected insects are dried and pinned in these boxes.
  • Larger animals like birds and mammals are usually preserved as stuffed specimens.
  • Skeletons of animals are also collected in the museums.

Question 4.
How is a zoological park helpful to scientists?
Answer:
It is difficult and dangerous to study ferocious animals in their natural habitats. Further, it is cruel to study them in captivity. So zoological park is a better option. Scientists can study different behavioural patterns, like feeding habits, mating rituals. This can help in a better understanding about them.

Long answer type questions

Question 1.
A student of taxonomy was puzzled when told by his professor to look for a key to identify a plant. He went to his friend to clarify what key the professor was referring to? What would the friend explain to him? [NCERT Exemplar]
Answer:
The key for identification of plants is a taxonomic key. It is a important taxonomic aid. Key can be defined as a set of alternate characters arranged in such a manner that by selection and elimination one can quickly find out the name of an organism. Depending upon the category, a key may be class key, order key, family key, genus key and species key.

Taxonomic keys can be of following two types:
(i) Indented or Yolked key
(ii) Bracketed key
Indented key, provides a sequence of two or more alternate characters from which selection and elimination are carried out. In bracketed key, the alternate characters are given numbers in brackets. For example, take four genera of family – Ranunculaceae to explain this,
(i) Ranunculus: Leaves alternate or radical, flowers not subtended by involucre, carpels ovuled, fruit achenes.
(ii) Clematis: Leaves opposite, compound petals absent, sepals 4, carpels uniovulated and fruit achenes.
(iii) Nigella: Flowers regular, carpels united at base, many ovulated, fruit follicles.
(iv) Anemone: Leaves alternate or radical, flowers subtended by involucre, carpels 1-ovulated, fruit achenes.

PSEB 11th Class Biology Important Questions Chapter 1 The Living World

Question 2.
Some of the properties of tissues are not the properties of constituents of its cells. Give three examples to support the statement. [NCERT Exemplar]
Answer:
A living thing has multiple level of organisation. Each level of organisaton i has its own properties, which are not found in its constituents.
Examples of three tissues supporting the statements are
(i) Cardiac muscle tissue: It is a contractile tissue present only in heart. Cell junctions fuse the plasma membrane of cardiac muscle cells and make them stick together. When one cell receives a signal to contract, its neighbours also starts to contract. It means a single cell cannot contract, while there are some fusion points, which allow the cells to contract as a unit.

(ii) Blood: It is a fluid connective tissue. The individual components of blood, i.e., RBCs, WBCs and platelets have different properties but as a unit they make the blood, a tissue serving many functions.

(iii) Bone: It is a hard connective tissue that forms the framework of the body. The individual cells inside the bone do not have this property.

PSEB 10th Class Science Important Questions Chapter 16 प्राकृतिक संसाधनों का संपोषित प्रबंधन

Punjab State Board PSEB 10th Class Science Important Questions Chapter 16 प्राकृतिक संसाधनों का संपोषित प्रबंधन Important Questions and Answers.

PSEB 10th Class Science Important Questions Chapter 16 प्राकृतिक संसाधनों का संपोषित प्रबंधन

दीर्घ उत्तरात्मक प्रश्न (Long Answer Type Questions)

प्रश्न 1.
वन्य संपदा की सुरक्षा के लिए कौन-कौन से उपाय हैं ?
उत्तर-
वन्य संपदा की सुरक्षा के उपाय-

  • वृक्षों को काटना बंद होना चाहिए।
  • केवल वे ही वृक्ष काटे जाएं तो सूख जाएं या जिन्हें कोई गंभीर बीमारी लग जाए और उनके स्थान पर नये वृक्ष लगाये जाने चाहिए।
  • वृक्षों की प्रति वर्ष गिनती की जानी चाहिए और वृक्षारोपण के लक्ष्य को पूर्ण करना चाहिए।
  • वन-महोत्सव मनाया जाना चाहिए। यह हमारे देश की वृक्षारोपण की परंपरा है जिसके अनुसार वनमहोत्सव सप्ताह में हज़ारों नये वृक्ष लगाये जाते हैं।
  • नये लगाए गए वृक्षों की देखभाल करनी चाहिए।
  • वनारोपण की नयी योजना लागू होनी चाहिए।
  • वन संपदा को जंगल की आग से बचाने के लिए उचित प्रबंध होना चाहिए।
  • वृक्षों को बीमारियों से बचाने के लिए रासायनिक दवाइयों का इस्तेमाल करना चाहिए।

प्रश्न 2.
पर्यावरण प्रदूषण के घटकों का वर्णन कीजिए।
उत्तर-
मानव तथा पर्यावरण का आपस में गहरा तथा अटूट संबंध है। मानव ही पर्यावरण को स्वच्छ या प्रदूषित करता है तथा उसका प्रभाव मानव को ही उसी रूप में प्रभावित करता है। मानव समाज के लिए स्वच्छ तथा स्वास्थ्यवर्धक पर्यावरण अति आवश्यक है। परंतु पर्यावरण को स्वच्छ और स्वास्थ्यवर्धक बनाना मनुष्यों पर ही निर्भर करता है।

मानव की क्रियाओं का अनियोजन होना पर्यावरण को उतनी ही अधिक हानि पहुंचाता है। महानगरों में ट्रकों तथा बसों से निकलता काला धुंआ, नदियों में नालों का गंदा पानी तथा सड़कों पर बिखरा कूड़ा-कर्कट आदि महानगरों के पर्यावरण को दूषित करते हैं। ये सभी क्रियाकलाप मिलजुल कर हमारे पर्यावरण के सभी घटकों जैसे-जल, वायु तथा मृदा के साथ-साथ हमें जीवित रखने के लिए अत्यंत आवश्यक हैं।

जनसंख्या में लगातार वृद्धि पर्यावरण को प्रदूषित करने में मानव की प्रमुख भूमिका है। जनसंख्या के बढ़ने से आवास, वस्त्र तथा खाद्य पदार्थों की आवश्यकता भी बढ़ जाती है। आवश्यकताओं को पूरा करने के लिए प्राकृतिक संपदाओं की हानि होती है। जैसे जंगलों को अत्यधिक काटा जाना; भूमिगत जल का अनियंत्रित उपयोग, जीवाश्म ईंधन का अत्यधिक उपयोग, औद्योगिकीकरण आदि। वे सभी किसी-न-किसी रूप में पर्यावरण को प्रदूषित करते हैं।

जब प्राकृतिक साधन पर्यावरण को पुनः स्वच्छता प्रदान नहीं कर सकते तो प्रदूषण होता है। औद्योगिक दुर्घटनाओं तथा बिना नियोजित लगाए गए कारखानों आदि से भी पर्यावरण प्रदूषित होता है। अत्यधिक रसायनों का उपयोग भी इसी का एक घटक है। प्राकृतिक संपदाओं का अतिशोषण भी पर्यावरण के प्रदूषण को बढ़ावा देता है। औद्योगिक क्रांति से वायु तथा जल प्रदूषण होता है। अम्लीय वर्षा, अंतः दहन इंजनों द्वारा प्रचलित वाहनों द्वारा अधिक मात्रा में सल्फर युक्त यौगिकों को वायु में मुक्त करने का परिणाम है। ऐरोसाल के उपयोग से ओजोन सतह की हानि हो रही है।

मानव के विभिन्न क्रियाकलापों के परिणाम से उत्पन्न अपशिष्ट पदार्थ पर्यावरण को प्रदूषित करने में सबसे आगे हैं। ये अपशिष्ट पदार्थ अत्यंत घातक होते हैं तथा इनका प्रभाव दूर-दूर तक फैल जाता है। इनका निपटान आजकल विश्व की समस्या है। इनका पुन: चक्रण ही पर्यावरण को प्रदूषित होने से बचा सकता है। पर्यावरण को प्रदूषित करने में मुख्य भूमिका मनुष्य की है, इसके साथ-साथ इस प्रदूषित पर्यावरण का शिकार भी प्रमुख रूप से मानव ही है।

PSEB 10th Class Science Important Questions Chapter 16 प्राकृतिक संसाधनों का संपोषित प्रबंधन

प्रश्न 3.
कोयला एवं पेट्रोलियम का प्रयोग सावधानीपूर्वक क्यों करना चाहिए ?
उत्तर-
कोयला और पेट्रोलियम पेड़-पौधों तथा जीव जंतुओं से बनते हैं जिनमें कार्बन के अतिरिक्त हाइड्रोजन, नाइट्रोजन एवं सल्फर भी होते हैं। जब इन्हें जलाया जाता है तो कार्बन डाइऑक्साइड, जल, नाइट्रोजन के ऑक्साइड तथा सल्फर के ऑक्साइड उत्पन्न होती हैं। अपर्याप्त वायु में जलाने पर कार्बन डाइऑक्साइड के स्थान पर मोनो ऑक्साइड उत्पन्न होती है। इन उत्पादों में से नाइट्रोजन और सल्फर के ऑक्साइड तथा कार्बन मोनोआक्साइड विषैली गैसें हैं। कार्बन डाइऑक्साइड एक ग्रीन हाउस गैस है।

कोयला और पेट्रोलियम कार्बन के विशाल भंडार हैं। यदि इनकी संपूर्ण मात्रा का कार्बन न जलाने पर कार्बन डाइऑक्साइड में परिवर्तित हो गया तो पृथ्वी पर ऑक्सीजन की उपलब्धता तो अत्यंत हो जाएगी पर साथ ही साथ कार्बन डाइऑक्साइड से अधिकता वैश्विक ऊष्मण होने का कारण बन जाएगी। इसलिए इन संसाधनों का उपयोग सावधानीपूर्वक करना चाहिए।

प्रश्न 4.
गंगा का प्रदूषण किस प्रकार हो रहा है ? इसकी सफाई योजना पर टिप्पणी कीजिए।
उत्तर-
गंगा हिमालय पर्वत में स्थित गंगोत्री से लेकर बंगाल की खाड़ी तक लगभग 2500 किलोमीटर तक यात्रा करती है। वह विभिन्न राज्यों के सौ से अधिक नगरों और कस्बों से गुजरती है जिस कारण उसमें तरह-तरह की गंदगियों का मिलना स्वाभाविक है।

गंगा का प्रदूषण मुख्य रूप से अग्रलिखित प्रकार का है-

  • औद्योगिक कचरा।
  • अनौपचारित मल और अपशिष्ट।
  • मृत शरीरों को तटों पर जलाना, जल में बहाना और मृत शरीरों की राख और हड्डियों को गंगा के जल में डालना।
  • अंधविश्वास के कारण गंगा में नहाना। गंगा की सफाई योजना गंगा के जल में धार्मिक कारणों से अस्थि प्रवाह किया जाता है।

इसलिए इसके जल में, मानव आंत में पाया जाने वाला कोलिफार्म जीवाणु उपस्थित है और उसकी MPN (Most Probable Number) जल के अधोप्रवाह में बढ़ता जाता है। सन् 1985 में, गंगा के प्रदूषण को दूर करने के लिए गंगा सफाई योजना शुरू की गयी थी। जिसका बजट प्रथम चरण में 462 करोड़ रुपये और द्वितीय चरण में 416 करोड़ रुपये था। इस अभियान के अनुसार 873 मिलियन लीटर जल प्रतिदिन उपचारित करना था। वर्तमान में गंगा की सफाई योजना में तेजी लाए जाने की परम आवश्यकता है तभी इसमें निरंतर बढ़ते प्रदूषण पर नियंत्रण पाया जा सकेगा।

लघु उत्तरात्मक प्रश्न (Short Answer Type Questions)

प्रश्न 1.
प्राकृतिक संसाधन को उदाहरण सहित परिभाषित कीजिए।
उत्तर-
प्राकृतिक संसाधन (Natural Resources)-प्रकृति में पाए जाने वाले मनुष्य के लिए उपयोगी पदार्थों को प्राकृतिक संसाधन कहते हैं। उदाहरण-वायु, जल, मिट्टी, खनिज, कोयला, पेट्रोलियम आदि प्राकृतिक संसाधन हैं।

प्रश्न 2.
3R के सिद्धांत से आप क्या समझते हो ? वर्णन करो।
उत्तर-
पहले ‘R’ का अर्थ है Reduce अर्थात् कम करना। इसका यह अर्थ है कि हमें कम-से-कम वस्तुओं का प्रयोग करना चाहिए। उदाहरण के लिए हम बिजली के पंखे तथा बल्ब के स्विच बंद करके विद्युत् के अपव्यय को रोक सकते हैं। इसी प्रकार कम-से-कम जल का उपयोग करके तथा लीक होने वाले नल तथा पाइप की मरम्मत करवा के भी हम जल के अपव्यय को रोक सकते हैं।

दूसरे ‘R’ का अर्थ है Recycle अर्थात् पुनः चक्रण। इसका अर्थ है कि हमें प्लास्टिक, कागज़, काँच, धातु की वस्तुएँ आदि पदार्थों का पुनः चक्रण करके इनसे उपयोगी वस्तुएँ बनानी चाहिएं। हमें ऐसी चीज़ों को कचरे के डिब्बे में नहीं डालना चाहिए बल्कि इन्हें अपने कचरे से अलग करना होगा ताकि यह दुबारा उपयोगी बनाई जा सकें।

तीसरा ‘R’ है Reuse अर्थात् पुन: उपयोग। यह पुन:चक्रण से भी अच्छा तरीका है क्योंकि पुनःचक्रण से भी कुछ न कुछ ऊर्जा व्यर्थ जाती है। पुन: उपयोग के तरीके में हम एक ही वस्तु का बार-बार उपयोग कर सकते हैं। उदाहरणविभिन्न खाद्य पदाथों के साथ आए डिब्बे तथा केन हम अन्य सामान रखने में प्रयोग कर सकते हैं।

PSEB 10th Class Science Important Questions Chapter 16 प्राकृतिक संसाधनों का संपोषित प्रबंधन

प्रश्न 3.
गंगा के जल प्रदूषण को किस प्रकार रोका जा सकता है ?
उत्तर-
गंगा के जल प्रदूषण को निम्नलिखित विधियों से रोका जा सकता है

  • औद्योगिक इकाइयों से निकलने वाले हानिकारक कचरे को गंगा में गिरने से रोक कर।
  • नदी में मृत पशुओं को बहाने से रोक कर।
  • घरों-व्यापारिक संस्थानों से निकले कूड़े को नदी में न बहा कर।
  • नदी में कपड़े न धो कर।
  • जल स्रोतों के निकट मल-मूत्र को न त्याग कर।
  • नदी में राख और शवों को न बहा कर।

प्रश्न 4.
पुनः चक्रण क्या है ? इसके लिए हम क्या कर सकते हैं ?
उत्तर-
पुनः चक्रण-पुरानी अखबारों, कॉपी-किताबों, धातु से बनी पुरानी-बेकार वस्तुओं, प्लास्टिक आदि को कुछ प्रक्रियाओं के द्वारा नए रूप में परिवर्तित किया जा सकता है, जिसे पुनः चक्रण कहते हैं। पुनः चक्रण के लिए हम अग्रलिखित कार्य कर सकते हैं-

  • ऐसी वस्तुएं खरीदें जिनका पुनः चक्रण संभव हो।
  • ऐसी वस्तुएं प्रयोग करें जो पुनः चक्रण से निर्मित हों।
  • पुन: चक्रण के लिए उपयुक्त वस्तुओं को खराब होने से पहले बेच दें।

प्रश्न 5.
‘चिपको आंदोलन’ ने सरकार तथा लोगों को क्या सिखाया है ? स्पष्ट कीजिए।
उत्तर-
चिपको आंदोलन-‘चिपको आंदोलन’ बहुत तेजी से विभिन्न समुदायों में फैल गया है। जन संचार माध्यमों ने भी इसमें महत्त्वपूर्ण योगदान दिया है। इसने सरकार को यह सोचने पर विवश कर दिया कि वन संसाधनों के समुचित उपयोग के लिए प्राथमिकता तय करने के लिए पुनर्विचार की आवश्यकता है। लोगों को अनुभव ने सिखा दिया है कि वनों के विनाश से केवल वन की उपलब्धता ही प्रभावित नहीं होती बल्कि मिट्टी की गुणवत्ता और जल स्रोत भी प्रभावित होते हैं। स्थानीय लोगों की भागीदारी निश्चित रूप से वनों के प्रबंधन में होनी चाहिए।

प्रश्न 6.
भौम जल के क्या लाभ हैं ?
उत्तर-
भौम जल के लाभ-

  • यह जल वाष्पित होकर वायुमंडल में मिलता नहीं है।
  • इसमें जीव जंतु तथा पादपों का जनन नहीं हो पाता।
  • यह भौम स्तर में सुधार लाता है।
  • यह पौधों को नमी प्रदान करता है।
  • यह जीव-जंतुओं के कारण प्रदूषित और संदूषित नहीं हो पाता।

प्रश्न 7.
जीवाश्म ईंधन क्या हैं तथा किस प्रकार बनते हैं ? इसके दो उदाहरण बताओ।
उत्तर-
जीवाश्म ईंधन-जंतु तथा वनस्पति के अवशेष पृथ्वी की सतह में दबते रहे हैं जो धीरे-धीरे तलछट के नीचे दब कर एकत्रित होते जाते हैं। इस प्रकार उन्हें ऑक्सीजन उपलब्ध नहीं होती। तलछट के आवरण के नीचे न तो इनका ऑक्सीकरण होता है और न ही विघटन, परंतु इसी तलछट के भार के कारण इन अवशेषों से पानी तथा अन्य वाष्पीजन्य पदार्थ निचुड़ कर बाहर निकल जाते हैं। इन्हीं पदार्थों को जीवाश्म ईंधन कहते हैं। जीवाश्म ईंधन ऊर्जा युक्त कार्बन यौगिकों के वे अणु हैं जिनका निर्माण मूलत: सौर ऊर्जा का उपयोग करते हुए वनस्पतियों ने किया था। जीवाश्म ईंधन के उदाहरण कोयला, पेट्रोलियम तथा प्राकृतिक गैस हैं।

प्रश्न 8.
“जल जीवन के लिए आवश्यक है।” इस कथन को सिद्ध कीजिए।
उत्तर-
जल निम्नलिखित कारणों से जीवन के लिए आवश्यक है

  • जल हमारे शरीर की सभी रासायनिक प्रक्रियाओं में भाग लेता है।
  • जल शरीर में तापमान को स्थिर रखता है।
  • जल पोषक पदार्थों को शरीर के विभिन्न भागों तक पहुँचाता है।
  • जल भल-मूत्र के विसर्जन में सहायता करता है।
  • जल पदार्थों के परिवहन में सहायता करता है।
  • कृषि, कारखानों तथा विद्युत् के लिए भी जल आवश्यक है।

PSEB 10th Class Science Important Questions Chapter 16 प्राकृतिक संसाधनों का संपोषित प्रबंधन

प्रश्न 9.
जल संरक्षण के कुछ प्रमुख उपाय लिखिए।
उत्तर-
जल के संरक्षण हेतु उपाय

  • जल को सिंचाई के लिए उपयोग करना।
  • बाढ़ नियंत्रण तथा हाइड्रोलोजिकल सर्वे और बाँध निर्माण करना।
  • भूमिगत जल की रिचार्जिंग तथा व्यय को रोकना।
  • अधिक जल तथा कम जल वाले स्थानों को स्थानांतरण करना।
  • मृदा अपरदन को रोकने के लिए बाह्य मृदा को बनाए रखना।

प्रश्न 10.
कुछ वायु प्रदूषकों के नाम लिखिए।
उत्तर-
वायु के मुख्य प्रदूषक निम्नलिखित हैं-

  • कार्बन मोनोक्साइड
  • कार्बन डाइऑक्साइड
  • सल्फर तथा नाइट्रोजन के ऑक्साइड
  • फ्लोराइडज के यौगिक
  • धातुएं तथा हाइड्रोकार्बन।

प्रश्न 11.
प्रदूषण नियंत्रण के पाँच उपाय बताओ।
उत्तर-
प्रदूषण को रोकने के लिए हमें निम्नलिखित उपाय करने चाहिएँ –

  • गोबर गैस का निर्माण करना चाहिए।
  • अजैव विघटनशील पदार्थों को गड्ढों में डालना चाहिए।
  • अपशिष्ट पदार्थों का चक्रीकरण करना चाहिए।
  • वाहित मल तथा उत्सर्जी पदार्थ आदि का सही ढंग से विसर्जन करना चाहिए।
  • आटोमोबाइल्स में सी० एन० जी० का प्रयोग करना चाहिए।

प्रश्न 12.
वनों के कटने से क्या हानि होती है ?
उत्तर-
यदि वृक्षों के कटने की दर उनकी वृद्धि से अधिक हो तो वृक्षों की संख्या धीरे-धीरे कम होती जाएगी। वृक्ष वाष्पण की क्रिया से बड़ी मात्रा में जल मुक्त करते हैं। इससे वर्षा वाले बादल आसानी से बनते हैं। जब वन कम हो जाते हैं तब उस क्षेत्र में वर्षा कम होती है। इससे वृक्ष कम संख्या में उग पाते हैं। इस प्रकार एक दुष्चक्र आरंभ हो जाता है और वह क्षेत्र रेगिस्तान भी बन सकता है। वृक्षों के बहुत अधिक मात्रा में कटने से जैव पदार्थों से समृद्ध मिट्टी की सबसे ऊपरी परत वर्षा के पानी के साथ बहकर लुप्त होने लगती है।

प्रश्न 13.
कोयला और पेट्रोलियम को किस प्रकार लंबे समय तक बचाया जा सकता है ?
उत्तर-
कोयला पेट्रोलियम का उपयोग मशीनों की दक्षता पर भी निर्भर करता है। यातायात के साधनों में आंतरिक दहन-इंजन का प्रयोग होता है। लंबे समय से इसके उपयोग के लिए शोध किया जा रहा है कि इनमें ईंधन का पूर्ण दहन किस प्रकार सुनिश्चित किया जा सकता है। यह भी प्रयत्न किया जा रहा है कि इनकी दक्षता भी बढ़े तथा वायु प्रदूषण को भी कम किया जा सके और इन्हें लंबे समय तक बचाया जा सके।

प्रश्न 14.
राष्ट्रीय उद्यान और वन्य जीव अभयारण्य में अंतर लिखिए।
उत्तर-

राष्ट्रीय उद्यान जीव अभयारण्य
(1) चीता, गैंडा, शेर आदि विशेष वन्य जीवों को आवास प्रदान किया जाता है। (1) जीव-जंतुओं की सामान्य प्रजातियों को प्राकृतिक वातावरण में सुरक्षा दी जाती है।
(2) क्षेत्र 100 वर्ग किलोमीटर से 500 वर्ग किलोमोटर तक होता है। (2) क्षेत्र 500 वर्ग किलोमीटर से 1000 वर्ग किलोमीटर तक होता है।
(3) चारों ओर पक्की दीवारें बनाई जाती हैं। (3) चारों ओर ऊँची जालीदार अस्थायी दीवारें बनाई जाती हैं।

अति लघु उत्तरात्मक प्रश्न (Very Short Answer Type Questions)

प्रश्न 1.
प्रदूषण क्या है?
उत्तर-
प्रदूषण-प्राकृतिक रूप में पाए जाने वाले अथवा शुद्ध रूप में पाए जाने वाले पदार्थों में धूल कण तथा अन्य नुकसानदेह पदार्थों का मिश्रण प्रदूषण कहलाता है।

प्रश्न 2.
किन्हीं पाँच प्राकृतिक संसाधनों के नाम बताएँ।
उत्तर-

  1. वन
  2. वन्य जीवन
  3. जल
  4. कोयला
  5. पेट्रोलियम।

PSEB 10th Class Science Important Questions Chapter 16 प्राकृतिक संसाधनों का संपोषित प्रबंधन

प्रश्न 3.
पर्यावरण को बचाने के लिए तीन R. के नाम बताएँ।
उत्तर-

  1. Reduce (कम करो)
  2. Recycle (पुनः चक्रण)
  3. Reuse (पुनः प्रयोग)।

प्रश्न 4.
किन वस्तुओं को पुनः चक्रण द्वारा दुबारा इस्तेमाल कर सकते हैं?
उत्तर-
प्लास्टिक, काँच, कागज़ एवं धातु की वस्तुएँ।

प्रश्न 5.
CFC का पूरा नाम बताएँ।
उत्तर-
क्लोरो फलोरो कार्बन।

प्रश्न 6.
ऊर्जा के अनवीकरणीय स्रोतों के उदाहरण दें।
उत्तर-
कोयला एवं पेट्रोलियम।

प्रश्न 7.
ऊर्जा के दो परंपरागत स्त्रोतों के नाम बताएँ।
उत्तर-
खनिज ईंधन और बहता हुआ पानी।

प्रश्न 8.
संसाधन यदि वर्तमान दर से प्रयोग में आते रहे तो यह कितने समय तक उपलब्ध रहेंगे ?
उत्तर-
पेट्रोलियम के संसाधन लगभग अगले 40 वर्षों तथा कोयले के संसाधन अगले 200 वर्षों तक उपलब्ध रह सकते हैं।

प्रश्न 9.
अपशिष्ट पदार्थों को किन दो वर्गों में रखा जा सकता है ? इनमें से कौन-सा अधिक घातक होता है ?
उत्तर-

  1. जैव निम्नीकरणीय अपशिष्ट पदार्थ।
  2. जैव अनिम्नीकरणीय अपशिष्ट पदार्थ। इन दोनों में से जैव अनिम्नीकरणीय पदार्थ अधिक घातक हैं।

वस्तुनिष्ठ प्रश्न (Objective Type Questions)
बहु-विकल्पीय प्रश्न

प्रश्न 1.
इंदिरा गाँधी नहर से किस राज्य के बड़े क्षेत्र को हरा-भरा बनाने में सहायता मिली ?
(a) उत्तर प्रदेश
(b) उत्तराखंड
(c) छत्तीसगढ़
(d) राजस्थान।
उत्तर-
(d) राजस्थान।

प्रश्न 2.
अमृता देवी बिश्नोई राष्ट्रीय पुरस्कार प्रदान किया जाता है
(a) जीव संरक्षण हेतु
(b) वनोन्मूलन हेतु
(c) वनों के विनाश को रोकने हेतु
(d) जल संरक्षण हेतु।
उत्तर-
(a) जीव संरक्षण हेतु।

प्रश्न 3.
जल संग्रह की “कुल्ह” तकनीक प्रचलन में है
(a) राजस्थान में
(b) हिमाचल प्रदेश में
(c) उत्तराखंड में
(d) मध्यप्रदेश में।
उत्तर-
(b) हिमाचल प्रदेश में।

PSEB 10th Class Science Important Questions Chapter 16 प्राकृतिक संसाधनों का संपोषित प्रबंधन

प्रश्न 4.
1970 के प्रथम दशक में चिपको आंदोलन कहां आरंभ हुआ ?
(a) कुमायुं में
(b) गढ़वाल में
(c) हिमाचल प्रदेश में
(d) असम में।
उत्तर-
(b) गढ़वाल में।

प्रश्न 5.
गंगा सफाई योजना कब आरंभ हुई ?
(a) 1945 में
(b) 1965 में
(c) 1985 में
(d) 2005 में।
उत्तर-
(c) 1985 में।

प्रश्न 6.
राष्ट्रीय वन पॉलिसी बनाई गई थी ?
(a) 1988
(b) 1989
(c) 1990
(d) 1991.
उत्तर-
(a) 1988.

प्रश्न 7.
पुनः चक्रण किया जा सकता है
(a) प्लास्टिक
(b) पॉलिथीन
(c) धातु
(d) इन सभी का।
उत्तर-
(d) इन सभी का।

रिक्त स्थानों की पूर्ति कीजिए-

(i) प्रकृति में मिलने वाले मनुष्य के लिए उपयोगी पदार्थों को ………………………. कहते हैं।
उत्तर-
प्राकृतिक संसाधन

(ii) ……………………… समाप्त होने वाला प्राकृतिक संसाधन है।
उत्तर-
मिट्टी

(iii) ……………………………… न समाप्त होने वाला प्राकृतिक संसाधन है।
उत्तर-
सौर ऊर्जा

PSEB 10th Class Science Important Questions Chapter 16 प्राकृतिक संसाधनों का संपोषित प्रबंधन

(iv) किसी बड़े क्षेत्र में अधिक वृक्ष लगाकर जंगलों को विकसित करना ………………………… कहलाता है।
उत्तर-
वनीकरण

(v) CFC का पूरा नाम …………………………. है।
उत्तर-
क्लोरो-फ्लोरो कार्बन।