Question

The filament of a bulb is usually a:
A. thin wire with many coils
B. thick wire with many coils
C. thin straight wire
D. thick straight wire

Answer 1

Hint: To know how the filament of a bulb is we need to know how the bulb works. A bulb is generally around a structure made up of glass in which there is a filament. This filament is the thing that glows in the bulb.

Complete step by step answer:
The filament of the bulb is generally a material which is of high resistance and high melting point. When current is passed through a material of high resistance the material gets heated up until it is red hot and this is the reason it produces light. That red hot filament of the bulb produces the light.
So to get high resistance cross-sectional area must be low, so the type of wire used is thin.
And the bulb must give a very efficient emission of light and to achieve that the wire is rounded into coils.
As the filament material, Tungsten is used as it is a material with high resistance and a high melting point as well.
Therefore, option A, which is a thin wire with many coils is the correct option.
Additional Information:
The invention of the first bulb was made by the great inventor and businessman of America Thomas Alva Edison.

Note: We can call a bulb as an electron-emitting element in a vacuum tube. Because emission of light is nothing but in simple words it is the emission of electrons from a surface. The resistance must be high for the filament of the bulb and the melting point must be high also.