Question

A light bulb has a resistance of 360 . What is the current in the bulb when it has a potential difference of 120 V across it?

A 0.33 A
B 3 A
C 480 A
D 43,200 A

Answer 1

The answer to the question is A. 0.33 A

Answer 2

The correct answer is option A. 0.33A.

According to the Ohm's Law, The current across the two points is directly propotional to the voltage and the equation is given below.

V ∝ i      (v is voltage or potential difference and i is current)

V = iR    ( Resistance)

Resistance is a constant, which is independent of the value of the current.

Given,

R = 360

V= 120 V

Putting value of R and V in V =iR

120 = 360 i

$\frac{120}{360} =i\\\frac{1}{3} =i\\i=0.33A$

Hence, the current in the bulb will be 0.33 A (ampere).