Using direct sunlight through the solar cooker, we can cook all types of food instead of using gas or electricity. Sunlight is nothing but the radiation which is generated by fluctuating magnetic and electric fields of the sun. The conversion of sunlight to heat occurs whenever the photons of light waves interact with molecules of any material. Possessing the energy of the sun emits electromagnetic radiation. When electromagnetic radiation is generated, the energy causes the material’s molecules to vibrate. Due to this, the molecule gets excited and jumps from a lower energy level to a higher one. Eventually, this activity generates heat.
Working Principle
The main working principle of solar cookers is to concentrate the sunlight, convert light energy into heat energy and trap this converted heat energy. There are four basic types of cooker, and they are:
- Panel cooker
- Box cooker
- Parabolic cooker
- Tube cooker
Each of these basic types of cooker meets a specific need and a specific kind of cooking. The most common type of solar cooker, which is mainly used, is the box-type solar cooker. This solar cooker comprises a black box, glass cover, plane mirror reflector, and cooking container.
Read More – Solar Cooker
Important Questions with Answers
1. Why is only black colour used in solar cookers?
In solar cookers, only black colour is used because it is a perfect absorber of heat energy. It helps absorb sunlight and does not allow the heat to escape. This is why solar cookers are painted by using only the black colour so that they can absorb the maximum amount of heat.
2. Which type of mirror is used in the solar cooker?
- Convex mirror
- Concave mirror
- Plane mirror
- None of the above
Answer: b. Concave mirror
Explanation: A concave mirror is used in a solar cooker because it reflects light falling onto it to a single focal point. A concave mirror absorbs all the incident light and reflects it to a single focal point. So, more heat gets generated.
3. Why is a solar cooker essential?
Burning fuels, such as gas and wood, pollute the air and contribute to climate change. The solar cooker is the most simple, safe, and convenient way to cook food without using cooking fuels. Solar cookers provide a pollution-free alternation. Without chimneys, cooking and heating on open fires or stoves lead to indoor air pollution. On the other hand, solar cookers help preserve nutrients, save money, are more convenient, prevent pollution, and save us from climate change.
4. What are the three main types of solar cookers?
The solar cooker is classified into three main types, and they are:
- Box cooker
- Parabolic cooker
- Panel cooker
5. What is the reason behind the shiny surface of the solar cooker?
The solar cooker has a shiny surface because it reflects extra sunlight onto the pot. This excess heat increases the heat potential.
6. Who invented the solar cooker?
- Sir Issac Newton
- Horace de Saussure
- Ampere
- Albert Einstein
Answer: b. Horace de Saussure
Explanation: The first solar box cooker was invented by Horace de Saussure.
7. How does the solar cooker concentrate the sunlight?
The high specular reflection mirror surface is used in a solar cooker to concentrate and channel sunlight from the sun into a tiny cooking space. Highly concentrated sunlight of several order magnitudes can melt salt and metal. But in household cooking, such a high temperature is not required. This is why the solar cooker available on the market is designed to achieve only 65-degree celsius to 400-degree celsius temperature.
8. What component is used in a box-type solar cooker?
The box-type solar cooker is made up of the following components:
- Black Box
In a box-type solar cooker, the box is constructed of insulating material or a wooden box. This box is painted black to absorb maximum heat from the sunlight.
- Glass Cover
A box-type solar cooker includes two sheets of hardened glass fitted together in an aluminium frame, used as the cover of box B.
- Plane Mirror Reflector
The plane mirror, which operates as a reflector, is set to box B with the help of the cover’s hinges. This mirror is placed at any desired angle that can allow the reflected sunlight to fall on the glass cover of the box.
- Cooking Containers
A set of metal containers constructed of aluminium are kept in box B. The boxes are always painted black colour from the outside to absorb maximum heat.
9. Solar cookers use fuel.
- True
- False
Answer: b. False
Explanation: Solar cookers do not use fuel. They save our expenses and prevent the environment from pollution.
10. Can a solar cooker work in cloudy weather?
Solar cookers are less useful in cloudy weather. This is the main disadvantage of solar cookers.
Practice Questions
- What are the advantages and disadvantages of solar cookers?
- How can we cook food by using sunlight?
- How do solar cookers convert light into heat energy?
- State and explain the working principle of box-type solar cookers.
- What is the role of the black box in a box-type solar cooker?
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