PSEB 8th Class Agriculture Solutions Chapter 4 Solar Energy

Punjab State Board PSEB 8th Class Agriculture Book Solutions Chapter 4 Solar Energy Textbook Exercise Questions and Answers.

PSEB Solutions for Class 8 Agriculture Chapter 4 Solar Energy

Agriculture Guide for Class 8 PSEB Solar Energy Textbook Questions and Answers

(A) Answer In one to two words:

Question 1.
What is the major benefit of solar water heater?
Answer:
It is used to heat water for temperatures less than 100°C.

Question 2.
Give two examples of renewable sources of energy.
Answer:
Solar energy, Bio-gas.

Question 3.
Give two examples of non-renewable sources of energy.
Answer:
Coal, Petroleum products etc.

Question 4.
How many types of solar dryers are?
Answer:
There are two types of solar dryer on the basis of their use domestic solar dryer and multi product solar dryer.

Question 5.
Name any two vegetables which are dried in the solar dryer.
Answer:
Spinach, Fenugreek, Chilli etc.

Question 6.
What is the capacity of multiple solar dryer for drying agricultural product?
Answer:
20 to 30 kg agricultural product.

Question 7.
What is the major benefit of solar cooker?
Answer:
It is used to cook food.

Question 8.
What percentage of conventional fuel can be saved by the use of solar cooker?
Answer:
It saves 20% to 50% conventional fuel.

Question 9.
For how many hours solar lantern can be used?
Answer:
For 3-4 hours.

Question 10.
How many types of solar cooker are there?
Answer:
These are of two types storage cum collector solar water heater and thermosiphon solar water heater.

(B) Answer in one to two sentences:

Question 1.
What are the types of energy sources? Give examples.
Answer:
There are two types of energy sources:

• Renewable
• Non-renewable.
• Renewable energy sources: Biogas, solar energy, chemical energy etc. These sources are plenty and less costly.
• Non-renewable energy sources: Electricity, coal, petrol etc. These are limited in nature.

Question 2.
Name the products which are dried with solar dryer.
Answer:
Spinach, tomato, fenugreek, mustard leaves, potato, turmeric, chilli, plums, peach, grapes etc.

Question 3.
What is meant by solar cooker?
Answer:
It is a device used to cook food using solar energy. It can save 20% to 50% of non-renewable fuel.

Question 4.
Briefly discuss solar street light.
Answer:
This light is used after the sun sets to light the street, roads etc. A battery is charged using solar energy which is used to give power to these solar lights. These are automatic lights which are operated automatically when sun sets.

Question 5.
What are the points kept in mind when the cooking is done in solar cooker?
Answer:

• Pre heat the solar cooker by setting up it in the sun.
• Add just sufficient water to the container having food ingredients to be cooked in the solar cooker.
• Vegetables, eggs etc. do not need water for cooking in solar cooker. Cut potatoes and vegetables into small pieces before placing these into the solar cooker for cooking.
• The container containing ingredients and water should not be filled more than half of its level.

Question 6.
Briefly discuss the solar home lighting system.
Answer:
In this system sunlight is used to charge the inverter battery system. It can be used to light 2 tube lights and two fans up to 5 to 6 hours in case of power cuts.

Question 7.
What is solar water pump?
Answer:
This pump is used to lift water from a level of 35 to 40 feet. It consists of a motor which runs by electricity produced by solar panels.

Question 8.
Briefly discuss solar lantern.
Answer:
This is an emergency light system. It is charged in the sun light and it can be used for 3-4 hours for lighting.

Question 9.
Briefly explain the working of domestic solar dryer.
Answer:
It is a small-sized solar dryer. It can be used to dry 2 to 3 kg fresh products in 2 to 3 days. Products which are dried in this dryer are normally used in powder form in the kitchen e.g. red chillies, onion, garlic, mango powder, ginger, spinach leaves etc.

Question 10.
Briefly discuss the multi-product solar drier.
Answer:
Agricultural products should be dried at low air temperature than the maximum allowed temperature. High temperature may destroy the quality of the food items. This solar drier can be used for drying 20-30 kg of agricultural products per day.

(C) Answer in five to six sentences:

Question 1.
Explain the method of cooking in solar cooker.
Answer:

• Pre heat the’solar cooker by setting up it in the sun.
• Add just sufficient water to the container having food ingredients to be cooked in the solar cooker.
• Vegetables, eggs etc. do not need water for cooking in solar cooker. Cut potatoes and vegetables into small pieces before placing-these into the solar cooker for cooking.
• The container containing ingredients and water should not be filled more than half of its level.
• Keep the top of solar cooker towards the sun.
• Do not open the solar cooker again and again. This will delay in cooking.
• Open the lid carefully after cooking the food, so that steam cannot hurt our body.
  

Question 2.
Explain the solar water heater in details.
Answer:
Solar water heater is a device used for heating water using solar energy. It consists of tubes, storage tank, tube and fix assembly, glass sheet etc.

Collector tubes are joined to the header of the bottom and top storage tank is insulated and is mounted in such a way that its bottom is above the top of collector by at least 60-70 cm. Front of the tube and fin assembly is covered by a glass sheet and all other sides and back are insulated. The sun rays fall on the tube and fin assembly, as a result water gets heated up, as hot water is lighter than cold water, hot water moves to the upper part of the storage tank.

Question 3.
Explain two solar dryer in detail.
Answer:
Solar dryer is used to dry vegetables and fruits. These are of two types.
Cabinet dryer:
This is a wooden box which is black from inside. It is covered with a glass sheet. Inside the box. there are perforated trays arranged at different levels, one above the other. Product to be dried is placed in these trays. There are two holes in this dryer, lower hole allows the air to enter and the hole at upper side allows the air to leave, this way air circulation takes place.

Multi product solar dryer:
This device is made up of sheets of wood and iron or of fiber glass. There are many holes at lower part and upper part for circulation of air. An arrangement has been done on the sides for placing and removing the products. There are shining rods for absorbing sunlight. Single glass sheet is fitted on the top of the box. Those trays which are used for drying the products have many holes in them. Trays are 3-4 cm in height. Cut pieces of vegetables and fruits can be dried in these trays. To protect the products from getting direct sunlight shining black plates are fixed. Since this is a solar device and uses sun rays it is placed in sunlight. Its glass top should be towards south.

Question 4.
Briefly discuss the different gadgets of solar energy.
Answer:
Do it yourself.

Question 5.
How the solar energy can be used in different ways?
Answer:
Sun is the ultimate source of energy in the world. Plants make their own food in sunlight and living beings take their food from the plants. Sun is responsible for air – water cycle, but all these things are happening automatically in nature. We can use solar energy in different ways by using different techniques, e.g.

• We can heat water using solar energy, cook food, produce electricity. We can dry fruits and vegetables using solar energy.
• Electricity can be produced using solar cells.
• We can save non-renewable sources of energy by using solar energy.

PSEB 8th Class Agriculture Guide Solar Energy Important Questions and Answers

Very Short Answer Type Questions

Question 1.
How many types of natural energy source are there?
Answer:
Two types.

Question 2.
What type of energy is electricity obtained from burning of coal?
Answer:
Conventional (Non-renewable) energy source.

Question 3.
Which type of energy sources are limited?
Answer:
Non-renewable.

Question 4.
Which type of energy sources are in plenty?
Answer:
Renewable (Non-conventional).

Question 5.
How much fresh product can be dried in domestic level solar dryer and in how many days?
Answer:
2-3 kg fresh products in 2-3 days.

Question 6.
Can we prepare chapati in solar cooker?
Answer:
No.

Question 7.
In which direction solar water should face?
Answer:
Towards south.

Question 8.
How many fans and lights can be operated using solar home lighting system?
Answer:
2 tubes, 2 fans for 5 to 6 hours.

Question 9.
What is the name of solar water heater.
Answer:
Thermosyphen solar water heater and storage-cum-collector solar water heater.

Question 10.
Name any one conventional source of energy.
Answer:
Coal.

Question 11.
How much percent of conventional fuel is saved by using solar cooker?
Answer:
20% to 50%.

Question 12.
Frame of trays is made up of which material?
Answer:
G.I. sheets.

Short Answer Type Questions

Question 1.
What are the uses of solar energy?
Answer:
Solar energy is used to heat water, for drying fruits and vegetables, for cooking food etc.

Question 2.
What is the disadvantage of drying bruits and vegetables in direct sun light?
Answer:
Insects, birds and dust can harm the fruits and vegetables and their color may change.

Question 3.
What is solar heater?
Answer:
This is a device which absorb solar energy and convert it in heat energy.

Question 4.
Why is it necessary to clean the glass of solar water heater?
Answer:
Dust collects on the glass which hinders the path of sun light and therefore efficiency of the water heater is reduced. It becomes necessary to clean the glass top.

Question 5.
How can solar energy be concentrated?
Answer:
By using various types of lenses and mirrors.

Long Answer Type Question

Question 1.
How much conventional fuel is saved by using solar cookers? What are the types of solar cookers? What are the limitations of solar cookers?
Answer:
By using a solar cookers we can save 20% to 50% of conventional fuel which is used to cook food. Solar energy can be concentrated by using various types of lenses, normally these are of two types:

1. Box type solar cooker
2. Double reflector solar cooker.

Limitations:
We have to Place the solar cooker in such a way that it is always facing The sunlight and it has to be set again and again. The solar cooker can not be used to prepare chapatis.