Topics
- 1. Electricity
- 2. Electric Cell
- 3. Electric Bulb
- 4. Electric Bulb connected to Electric Cell
- 5. Electric Circuit
- 6. Electric Switch
- 7. Conductors and Insulators
Electricity is the flow of electric charge. It provides energy or power that is used to run electrical and electronic appliances.
- Electricity is used for running electrical appliances like fan, tube light, water pumps etc and electronic appliances like TV, Computer, washing machines, radio etc.
- Electricity is generated through thermal power stations, windmills, batteries etc.
Electric Cell
An electric cell is a device which produces electricity capable to run smaller appliances like torch, clock, camera, radio etc.
- An electric cell has twoย terminalsย โย positive (+)ย andย negative (-).
- Positive side of an electric cell has a metal cap. Negative side has a flat metal disc.
- Chemicals stored inside the cell produce electricity through internal reactions. Once, chemicals are used up, the cell loses its capability to produce electricity.
Electric Bulb
An electric bulb is a device which produces light when electricity is passed through its terminals.
- The bulb has two thick contact wires in the center with a thin wire attached between them. This thin wire is calledย filament.
- One of the thick wires is connected to the metal case at the base of the bulb and the other is connected to the metal tip at the center of the base. These two form the terminals.
- When electricity is passed through the terminals of the bulb, the filament gets heated up and produces light.
- A bulb is said to be fused if the filament gets broken. Fused bulb doesnโt glow.
- The two terminals do not directly touch each other to avoid short circuit.
Electric Bulb connected to Electric Cell
An electric cellproduces electricity capable enough to make a bulb glow.
- To make a bulb glow using a cell, a wire needs to be connected from one terminal of the cell to one terminal of the bulb. Similarly, the other terminal of the cell must be connected to second terminal of the bulb.
- The bulb will not glow in case the above is not followed and the connections are not made properly.
Electric Circuit
An electric circuit is a complete path for electricity (current) to pass between two terminals of an electric cell.
- Bulb glows when current flows through its terminals.
- Conventionally, current flows from positive terminal to the negative terminal of the battery.
- A fused bulb (with broken filament) offers a broken path and hence the bulb doesnโt glow.
Electric Switch
Electric Switch is an electrical device which can make or break an electric circuit.
- A switch is said to be inย โONโ positionย when itย makes or completes the circuitย and allows the current to pass through.
- Similarly, a switch is inย โOFFโ positionย when itย breaks the circuitย and does not allow the current to pass through.
Conductors and Insulators
- Materials which allow electric current to pass through them are called conductors of electricity. Examples are iron nail, key, safety pin, water, human bodyetc.
- Materials which do not allow electric current to pass through them are called insulators of electricity. Examples are rubber, plastic, glass, air, clothetc.
- Conductors are mainly metallic while insulators are non-metallic.
- Electrical devices are made up of conductors. To avoid passing of the current to human body during their handling, these devices have a covering of insulators (like plastic, wood, aluminum) over them.
