3
Question Question 3
An electric iron of resistance 20 Ω takes a current of 5 A. Calculate the heat developed in 30 s.
Given,
R = 20 Ω
I = 5 A
t = 30 s
According to Joule's law of heating,
H = I2Rt
Substituting the values, we get,
H = 5 x 5 x 20 x 30 = 15000 J
Therefore, amount of heat developed = 15000 J.