Question

An electric iron of resistance 20 ohm takes a current of 5ampear calculate the heat developed in 30sec

Answer 1

Given
Resistance r=20ohm
Current i=5Amp
time t=30sec
$wkt \\ q = {i}^{2} rt \\ q = {5}^{2} \times 20 \times 30 \\ q = 15000joules \\ q = 15kj$
hope it helps

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