# Energy: The Property of Objects, Unit of Energy, Forms of Energy (For CBSE, ICSE, IAS, NET, NRA 2022)

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# Energy: The Property of Objects

## Definition of Energy “Energy is the Ability to Do Work”

• Physical or chemical resources are processed to generate energy which is further used to provide light or heat for domestic or industrial purposes.
• Different types of energy which can never be created nor destroyed.
• Energy can only be transformed from one form to another.

### Unit of Energy

• The SI unit of energy is Joules (J) which is nothing but a term for Newton-meter.
• When a certain amount of force (Newton) is applied to an object and it moved a certain distance (meters) , then the energy applied is said to be Joules (newton-meters) .

### Forms of Energy

• There are two types of energy:
• Kinetic energy (working)
• Potential energy (static)
• There are two forms of energy sources:
• Renewable source of energy
• Non-renewable source of energy

Following are the examples of types of energy based on their sources:

• Renewable source:
• Solar energy
• Wind energy
• Geothermal energy
• Non-renewable source:
• Natural gas
• Coal
• Petroleum products

### Types of Energy

• There are different forms of energy but the distinction between them is not always clear.
• As Richard Feynman, a famous physicist once said, “The notions of potential and kinetic energy depend on a notion of length scale.”
• As an Example, one can speak of macroscopic potential and kinetic energy, which do not include thermal potential and kinetic energy.
• Also, what is called chemical potential energy is a macroscopic notion, and closer examination shows that it is really the sum of the potential and kinetic energy on the atomic and subatomic scale.
• Same remarks apply to nuclear “potential” energy and most other forms of energy.

### Kinetic Energy

The energy in motion is known as Kinetic Energy. For example, a moving ball, flowing water, etc.

Where,

m = Mass of the object

v = Velocity of the object

### Potential Energy

This is the energy stored in an object and is measured by the amount of work done. For example, a pen on a table, water in a lake, etc.

Where,

• m = Mass of the object (in kilograms)
• g = Acceleration due to gravity
• h = Height in meters

### Mechanical Energy

It is the sum of potential energy and kinetic energy that is the energy associated with the motion & position of an object is known as Mechanical energy. Thus, we can derive the formula of mechanical energy as –

### Solar Energy

• The light and heat from the sun, harnessed using technologies like, solar heating, photovoltaic՚s, solar thermal energy, solar architecture, and artificial photosynthesis is known as solar energy.
• It is the prime source of renewable energy.

### Wind Energy

• It is one of the various forms of energy. The energy present in the flow of wind, used by wind turbines is called wind energy. This energy is a major cheap source to produce electricity.
• In these phenomena, the kinetic energy of the wind is converted into mechanical power.

### Nuclear Energy

• The energy present in the nucleus of an atom is known as nuclear energy.
• The particles of an atom are tiny and need the energy to hold themselves.
• Nuclear energy is that enormous energy in the bonds of an atom which helps to hold the atom together.
• It can be used to make electricity.

### Geothermal Energy

• The energy or heat present inside the Earth is known as geothermal energy.
• It is a cheap & convenient heat and power resource and use of this energy don՚t have a side effect like greenhouse gas emission etc.

### Tidal Energy

Tidal energy or tidal power is a form of hydropower (energy present in water) , which converts the energy present in the tides to produce electricity.

### Biomass Energy

Biomass is organic matter obtained from living organisms. The energy produced from biomass is called biomass energy.

### Electrical Energy

The energy caused by moving electric charges is known as electrical energy. Electric energy is a type of kinetic energy as the electrical charges moves.

### Thermal Energy

• As the name suggests, thermal energy is the energy obtained from heat. It is a microscopic, disordered equivalent of mechanical energy.
• There may be instances where an object posses more than one type of energy. For example, boiling water, posses both kinetic and potential energy along with heat energy.

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