Pg:- 108,109

Ch:- 6

Energy transfer in an electrical circuit occurs when electrical energy is converted into other forms of energy, such as heat, light, or mechanical energy.

Components of Energy Transfer in a Circuit:

1. Energy Source:

   • The energy source, such as a battery or generator, provides electrical energy.

   • In a battery, chemical energy is converted into electrical energy.

   • In a generator, mechanical energy is converted into electrical energy.

2. Electric Current:

   • Electric current is the flow of electric charge (usually electrons) through the circuit.

   • Current carries energy from the source to other components in the circuit.

3. Circuit Components:

   • Resistors: Convert electrical energy into heat (e.g., in a heater).

   • Light Bulbs: Convert electrical energy into light and heat.

   • Motors: Convert electrical energy into mechanical energy.

   • Capacitors and Inductors: Temporarily store energy and release it later.

Mechanism of Energy Transfer:

1. Potential Difference (Voltage):

   • The source creates a potential difference across the circuit, providing the "push" that moves charges.

   • Voltage represents the energy transferred per unit charge.

2. Work Done on Charges:

   • Charges gain energy as they pass through the source and lose energy as they pass through resistive components or perform work.

3. Power in the Circuit:

   • Power (P) is the rate at which energy is transferred.

   • It is calculated as: P=IV Where I is current and V is voltage.

   • Power can also be expressed in terms of resistance (R) as: P=I^2 R

Energy Conservation in Circuits:

• Energy is conserved in a closed circuit.

• The electrical energy supplied by the source is equal to the total energy converted by the components.

• If E is the total energy supplied by the source: E= ∑ Energy dissipated by components (e.g., resistors, light bulbs, etc.)..

Example:

In a simple circuit with a battery and a resistor:

1. The battery provides energy by creating a potential difference.

2. Electrons flow through the circuit, transferring energy to the resistor.

3. The resistor converts electrical energy into heat (or light in some cases).