Question

A heater coil is cut in two pairs of equal length and only one of them is used in the heater. The ratio of the heat produced by this half coil to that by the original coil is

• A. 2 : 1
• B. 1 : 2
• C. 1 : 4
• D. 4 : 1

Answer 1

The correct option is B 1 : 2

Heat power=$P=I^{2}R=I^2\rho \frac{L}{A}$

Hence, $P\propto L$

Hence, required ratio is $1:2$

Answer_(B)