Forms of Energy
There are many forms of energy. And one type of energy can also be converted into another type of energy.
1. Mechanical energy
The energy present in an object due to its state or motion is called mechanical energy, such as a keyed clock coil has mechanical energy. Similarly, there is also mechanical energy in flowing water or in a moving car.
2. Chemical Energy
All substances are made up of molecules. Compounds are formed when molecules of different substances combine. Some energy is hidden in these molecules and compounds. When a chemical change occurs, this hidden energy, called chemical energy, is produced in many forms.
For example, before burning a matchstick, it contains chemical energy, but after burning it turns into thermal and light energy.
3. Sound energy
Sound is another form of energy. It will be difficult to see that an object can be moved by sound, but when the sound waves produce vibrations on the screen of our ears, then only we are able to hear.
When there is a big explosion with a loud sound, the doors and windows of the houses start rattling. Since sound can rattle windows and doors, it is also a form of energy.
4. Thermal energy
When the water starts boiling in the steel vessel, the lid placed on it starts rising upwards due to steam. At normal temperature, the water cannot lift the lid but when heated to boiling, it becomes hot vapor i.e. steam and now it has thermal energy and it can lift the lid. Hence heat is a form of energy.
5. Optical energy
Since light is a weak form of energy, it is not able to produce motion in heavy objects. However, it can affect the photographic film. This can cause displacement in light dust particles. The light emitted from a bulb or tube light is optical energy.
Hidden-bell is a device that works on optical energy. Light energy is incident on an optical cell (photo cell) and the bell starts ringing. When a thief enters the house, this photo stops the light imported from the cell and starts ringing.
6. Electrical energy
Electric energy is one of the most used energy in our daily life. We switch on the bulb and light is generated due to the current flowing in the bulb. Similarly, electric energy is used in the fan; tube well, air conditioning, fridge, mixer and many other household appliances.
7. Magnetic energy
A magnet can attract (pull) iron shavings or pins. In many factories, cranes will be found to separate the iron from the pile of waste. Very large electromagnets are used in these.
Different types of energy can be converted into each other. For example in the thermal power house, the chemical energy of coal is first converted into thermal energy of hot steam, then it is converted into mechanical energy of turbine. This energy is converted into electrical energy by the generator, which flows into electrical wires and reaches various places - houses, factories, etc., where it is again converted into heat, light, sound or mechanical energy.
Unit of energy
If an object is displaced by a meter distance by applying a Newton force, the energy spent in doing so is one joule of energy. Hence the unit of energy is joule.