Q. A heater of 220 V heats a volume of water in 5 min time. A heater of 110 V heats the same volume of water is
A) 5 min
B) 8 min
C) $4 \times 10^{4}\ $min
D) 20 min
Explanation
(d) Heat produced, $H = \frac{V^{2}t}{R}.$ When voltage is halved, the heat produced becomes one-fourth. Hence time taken to heat the water becomes four time.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.