The torch/flash light 

Uses of parts of a torch


1. Reflector:  Directs lights into a parallel beam of light.

2. Bulb: It produces light.

              It changes electric energy to heat then to light.
3. Dry cells: It is the source of electric energy. 
4. Glass: It protects the bulb and reflector.
5. Switch: Breaks and completes the circuit at the users wish.
6. Cover and springs: Keep the dry cells tightly together.

The Electric Bulb.                                   

bulb

Uses of parts of a bulb
1. Filament: It produces light.

             It is made of tungsten from a mineral called wolfram

Adaptation of the filament for its function.

  • It has a high melting point.
  • It is coiled to increase electric resistance

2. Conducting wire: It conducts electricity to the filament.
3. Glass: Protects the inside parts of the bulb.

               It prevents nitrogen and argon gases from escaping.

               It is  transparent to allow light to pass through.
4. Filament support: It supports the filament.
5. Contact: It allows electricity into the bulb.
6. Insulating material: It separates the conducting wires. 

Question

  1. Why is a filament of an electric bulb coiled?
  2. State any component of a circuit that use an  alloy.
  3. How is the reflector important in an electric torch?
  4. Which gas is commonly used in electric bulbs?
  5. Give one reason why the glass of a bulb is transparent?