Question

A heater coil is cut into two equal parts and only one part is used in the heater, the heat generated becomes

• A. one fourth
• B. Halved
• C. Doubled
• D. four times

Answer 1

Answer: (C)

Doubled

Answer 2

Earlier heat generated was $Q_1 = \frac{V^2 \, t}{R}$ When half of the coil is used, the resistance is halved . $\therefore$ the heat generated is $Q_2 = \frac{V^2 t}{(R/2)} = 2 \, Q_1$