Question

When a current of 4.0 A passes through a certain resistor for 10 minutes, 2.88 x 10⁴ J of heat are produced. Calculate :

(a) the power of the resistor.

(b) the voltage across the resistor

Answer 1

Given I = 4 amp, t = 10min = 10 x 60 = 600sec, H = 2.88 x 10⁴J

(a) We have

H = I²RT

28800 = 4² x R X 600

R = 3 ohms

We know that

P = I² x R

= 4² x 3

P = 48 W

(b) V = ?

we know that

V = IR

V = 4 x 3

V = 12V