Question

An electric iron of resistence 20 ohm takes a current of 5 ampere. calculate the heat develops in 30 seconds

Answer 1

Hello dear

HERE IS THE ANSWER

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

$Now \: we \: know \: that \: H= {I }^{2} Rt$

Putting the values we get:-

 = 5×5×20×30

= 15000J
=1.5×10^4J

∴ The heat developed in 30s is 1.5×10^4J

Hope it helps you.

Answer 2

Given,

Resistance (R) = 20Ω

Time(T) = 30 seconds

Current (i) = 5A

We know that heat develops in restitance of R in Time t is

$H = \frac{i^{2}RT}{4.2} \ cal. \\ \\ = \frac{5^{2}*20*30}{4.2} \ cal \\ \\ = \frac{15000}{4.2} \ cal \\ \\ = 3571.42 \ cal$