Question

an electric iron of resistance 20 ohm takes a current of 5A. calculate the heat developed in 30 seconds

Answer 1

h=i^2rt
h = 5^2 * 20 * 30
h = 15000 j

Answer 2

howdy !!

your answer is --

Given, resistance R = 20ohm ,
current I = 5A & time t = 30sec

we know that
$heat = {current}^{2} \times resistance \times time \\ = > h = {i}^{2} \times r \times t$
now put the given value , we get
$h = {5}^{2} \times 20 \times 30 = 25 \times 600 \\ \: \: \: \: \: \: = 15000joule$

hope it help you