Question

A current of 0.4 A is flowing through a conductor having resistance of 100 Ω. It generates a heat of 1200 J. For how much time the current is flowing through the conductor?

• A. 65 s
• B. 85 s
• C. 75 s
• D. 75 min

Answer 1

The correct option is C 75 s

Here, its given that I = 0.4 A, R = 100 Ω, H = 1200 J
We know that $H=I^{2}Rt$
And on solving for t, $t=\frac{H}{I^{2}R}$
$\Rightarrow t=\frac{1200}{{0.4}^2\times 100}=75s$