Sources of Electric current

Sources of Electric Current

Electric current can be generated from the following sources:

1. Chemical energy:Electrical cells store chemical energy. There are two types of electrical cell. The primary cell and the secondary cell. The primary cell cannot be recharged while the secondary cell can be recharged.
2. Heat Energy: Electricity can be generated by thermoelectric effect using a thermocouple, which consists of two different metallic wires joined and dipped in hot water while the other end is connected to a sensitive galvanometer.
3. Mechanical Energy: Current can be obtained from the generator. The generator converts mechanical  energy to electrical energy by the principle of electromagnetic induction.
4. Solar Energy: Electricity can be generated from solar energy using the solar cell. In the solar cell solar energy is converted to electrical energy.

GENERAL EVALUATION

1. Explain at least three sources of generating electricity.

(a) Define electric field.

(b)  Draw the electric field pattern around two unlike charges.

2. (a) Define the electromotive force and terminal potential difference of a battery.

(b) Explain why the electromotive force of a cell is not always the same as the potential difference between its terminals.