Question

A bulb in an electric circuit glows due to:
A. Magnetic effect of current
B. Heating effect of current
C. Chemical effect
D. Conduction of current

Answer 1

Hint:Here we can use the concept of Joule’s heating effect on a given metallic conductor in which electric current is passed and explain how much heat is generated when current passes through the metallic conductor.

Complete step by step answer:
The Joule’s heating effect can also be called ohmic heating. In the effect, whenever an electric current is passed through a metallic conductor, the flow of free electrons begins to move rapidly and thus causes a heating effect on the conductor.
According to the Joule’s first law, the amount of heat developed in the metallic conductor after passing electricity on it is directly proportional to the product of its resistance and the square of the current. Mathematically, we have, $P\propto {I^2}R$, where $P$ is the amount of heat developed in the metallic conductor after passing electric current on it.
$I$ is the amount of electric current passed through the metallic conductor.
$R$ is the Resistance of the metallic conductor on which the electric current is passed.
The S.I. unit of $I$ is Ampere $(A)$ and $R$ is $ohms(\Omega )$
Hence, when an electric current is passed through the filament of the bulb, it first gets heated due to the high resistance property and after coming in contact with the chemical inside the seated bulb, the bulb begins to glow. Hence a bulb in an electric circuit glows due to the heating effect of current.
Therefore, from the above explanation, the correct option is (B) Heating effect of current.

Note:The filament which has a high melting point material is a good conductor of heat and electricity. An example of such filaments used in a bulb is tungsten. Also remember that higher amount of current leads to generate a high amount of heating effect in the conductor.