Question

The heating element of an electric toaster has a resistance of 22 $\Omega$ and is connected to an ordinary house lighting circuit of 100 V . If J = 4.2 J/cal , the heat generated in 1 minute is

• A. 26.19 cal.
• B. 130.95 cal.
• C. 7857 cal.
• D. 6493 cal.

Answer 1

The correct option is C 7857 cal.

We have the equation,

Power, $P=VI=\frac{V^2}{R}$

$=\frac{110\times 110}{22}watt=550watt$

Also,

Heat generated, $H=\frac{P\times t}{J}$

$=\frac{550\times 1\times 60}{4.2}cal=7857cal$