Question

An electric iron of resistance 20 ohm takes a current of 5 ampere.calculate the heat developed in 30 second

Answer 1

(R) = 20 Ω

(I)= 5 A  

(t)= 30 s

Now we know that H= I2Rt

                        use it here     = 5×5×20×30

                               = 15000J=1.5×104J

The heat developed in 30s is 1.5×104J

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