Question

An electric iron of resistance 20 ohm's takes a current of 5 amphere. Calculate the heat developed in 30 seconds?

Answer 1

HEAT = I^2 RT
= 5 *5 * 20 * 30
= 25 * 600
= 15000

Answer 2

Given :-

R = 20 Ω

I = 5 A

t = 30 s

H = I^2Rt

= (5)^2×20×30

= 15000 J

= 1.5 × 10^4 J