Question

The heating element connected to 220 V draws a current of 4 A. Determine the amount of heat dissipated in 15 minutes. (J=4.2J/cal)

Answer 1

Given,

$V=220V$

$I=4A$

$t=15min=15\times 60=900sec$

Resistance, $R=\frac{V}{I}=\frac{220}{4}=55\Omega$

The amount of heat dissipated is given by

$H=I^{2}Rt$

$H=4\times 4\times 55\times 900$

$H=792kJs$