JEE Main · 2005 · 08 May 2005 · Offline · Current Electricity

A heater coil is cut into two equal parts and only one part is now used in the heater. The heat generated will now be

Answer: (A)

Solution

At the same supply voltage the heat produced is

H = \frac{V ^{2} t}{R}

. Cutting the coil in half halves its resistance to

\frac{R}{2}

, so using one half gives

H^{'} = \frac{V ^{2} t}{R /2} = 2 \frac{V ^{2} t}{R} = 2 H

: the heat generated is doubled.

JEE Main · 2005 · 08 May 2005 · Offline · Single correct option