Question

Question 3
An electric iron of resistance $20\Omega$ takes a current of 5 A. Calculate the heat developed in 30 s.

Answer 1

The amount of heat (H) produced is given by Joule's law of heating as, H = Vlt
Here, Current, I = 5 A
Time, t = 30 s
Voltage, $V=\left(I\right)Current\times \left(R\right)Resistance=5\times 20=100V$
$H=100\times 5\times 30=15\times {10}^{3}J=1.5\times {10}^{4}J$
Therefore, the amount of heat developed in the electric iron is $1.5\times {10}^{4}J$.