Q. An electric heater of resistances 6 $\Omega$ is run for 10 min on 120 V line. The energy librated in this period of time is?
A) $7.2 \times 10^{5}$ J
B) 14.4$\ \times 10^{5}$ J
C) 43.2$\ \times 10^{5}$ J
D) 28.8$\ \times 10^{5}$ J
Explanation
(b) Energy liberated $= \frac{V^{2}}{R}t$
$\ = \frac{(120)^{2}}{6} \times (10 \times 60) = 14.4 \times 10^{5}$ J
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.