Question

an electric resistor of 20 ohms draws a current of 5a calculate the heat produced by its in 30 sec

Answer 1

Solution:

Given that Resistance(R) = 20 Ω, Electric current (I)= 5 A and time(t)= 30 s

Now we know that H= I2Rt

                                = 5×5×20×30

                                = 15000J=1.5×104J

∴ The heat developed in 30s is 1.5×104J

Answer 2

give R= 20 ohm I = 5A and t= 30sec
heat produced = I^2×R×t
= 25×20×30
= 15000J