Question

- In any electric circuit, when the switch is on and the current is flowing through it why do the wire, switches, bulb or devices in the circuit become hot?
A. Because of the heating effect of electric current
B Because of the magnetic effect of electric current
C. Because of the luminous effect of electric current
D. None of these

Answer 1

The current generated in any electric circuit is due to the flow of electrons. These electrons flow within electric wires to all the devices connected by these electric wires and these electrons are produced from any power generating device.

Complete step by step answer:
We know that the motion of charge carriers is responsible for generating the current. The movement of current is from positive to negative terminal. The current flows in the conductor to provide the desired effect.

To form a proper circuit, the devices that included forming a circuit are battery, wire, switches and bulb. The desired effect of current in this circuit is to glow the bulb.

According to ohm’s law, the voltage is proportional to the current and resistance.
$V = IR$
By the above relation we can observe that, the current is inversely related to the resistance. So, if the current is more, then the resistance becomes less or vice versa. But it is not possible that there is no resistance. There is some resistance that restricts the flow of current.

According to the Joule’s law of heating,
$H = {i^2}Rt$
From this relation, we can conclude that the heat energy is proportional to the square of the current supplied and resistance of the conductor for a time(s). So, if current flows in the circuit the heat is generated in the device and causes the device to heat.

Therefore, the correct option is (A).

Note:
In this question, we have knowledge of electric current and generation of electric current. If we increase more and more current to remove the resistance, which is practically not possible because if we increase more current, then there is a chance of an electric device to burst. There is some limit that an electric device can bear that amount of current.