Question

1.What is energy?
List four forms in which energy exists. Give one way in which each used
2. What is a fuel? Name one fuel that is renewable and three fuels that are non-renewable
9. Give two examples of renewable energy sources and say why they are considered
to be renewable.
10. How is energy of flowing water used to generate electricity?​

Answer 1

Answer:

1. Energy is the quantitative property that must be transferred to an object in order to perform work.

Energy exists in many different forms. Examples of these are: light energy, heat energy, mechanical energy, gravitational energy, electrical energy, sound energy, chemical energy, nuclear or atomic energy and so on. Each form can be converted or changed into the other forms.

Electrical Energy

Electrical energy is the energy carried by moving electrons in an electric conductor. It is one of the most common and useful forms of energy. Example – Lightning. Other forms of energy are also converted to electrical energy. For example, power plants convert chemical energy stored in fuels like coal into electricity through various changes in its form.

Mechanical Energy

Mechanical energy is the energy a substance or system has because of its motion. For example machines use mechanical energy to do work.

Thermal energy

Thermal energy is the energy a substance or system has related to its temperature, i.e., the energy of moving or vibrating molecules. For example, we use the solar radiation to cook food.

Nuclear energy

Nuclear energy is the energy that is trapped inside each atom. Nuclear energy can be produced either by the fusion (combining atoms) or fission (splitting of atoms) process. The fission process is the widely used method.

2. Any substance that can provide heat and produce energy when it is burned is called fuel.

Renewable fuel :- Biofuel

Non renewable fuel:- Oil, natural gas, coal

9. The following sources of energy are renewable:

(i) Wind energy is renewable as winds will be moving as long as the normal behavior of the weather and our environment persists.

(ii) Hydro energy is renewable as hydro energy can be harnessed as long as the flowing water bodies like rivers and waterfalls exist.

10.The electricity generated from hydro power plant is known as hydro electricity. Water is collected in a reservoir at a height, so the water has potential energy stored in it. When the water flows down through this large height, its potential energy gets converted into kinetic energy. The fast flowing water rotates the turbine which is connected to generator through its shaft. The generator produces electricity.