Question

A car headlamp of 48 W works on the car battery of 12 V. The correct fuse for the circuit of this car headlamp will be:

(a) 5 A
(b) 10 A
(c) 3 A
(d) 13 A

Answer 1

(a) 5 A
It is given that:
Power, P = 48 W
Potential difference, V = 12 V
We know that:
P = V $\times$ I
Therefore, current, I = P / V
= 48 / 12 = 4 A
We should use a fuse with current capacity slightly greater than the maximum current drawn by the device. Thus, the value of correct fuse for the circuit will be 5 A and the fuse wire will melt if the value of current exceeds 5 A.