The filament of a bulb is made extremely thin and long in order to achieve:

Correct option is A

The filament of a bulb is made extremely thin and long to achieve high resistance. In an electric bulb, the filament is typically made of tungsten, which has a high melting point and can tolerate high temperatures. By making the filament thin and long, its resistance increases significantly. This high resistance causes the filament to heat up when current passes through it, eventually producing light. The thin and long design ensures that the filament has a sufficient resistance to produce the necessary heat and light efficiently.

Important Key Points:

1. High resistance is achieved by making the filament thin and long, which helps convert electrical energy into heat and light.
2. The filament material, typically tungsten, has a high melting point and can withstand extreme temperatures.
3. Increasing the length and reducing the cross-sectional area of the filament increases its resistance.
4. The high resistance ensures that the filament glows when current passes through it, providing light.
5. The design of the filament plays a crucial role in the energy efficiency and lifespan of the bulb.
6. Ohm’s law (V = IR) shows that resistance is inversely proportional to the cross-sectional area of the filament, hence a thinner filament leads to higher resistance.