Charge is flowing through a conductor at the rate of 420 C/min. If 742 J. of electrical energy are converted to heat in 30 s., what is the potential drop across the conductor?

3.53 V

Explanation:

Electric charge: The is the rate of flow of electric charge along a conductor.

The S. I unit of electric charge is C.

Mathematically it is expressed as,

Q = It ... Equation 1

Where Q = electric charge, I = current, t = time.

I = Q/t ... Equation 2

From the question, charge flows through the conductor at the rate of 420 C/mim

Which means in 1 min, 420 C of charge flows through the conductor.

Hence,

Q = 420 C, t = 1 min = 60 seconds

Substitute into equation 2

I = 420/60

I = 7 A

Also

P = VI ... Equation 3

Where P = power, V = potential drop, I = current.

V = P/I ... Equation 4

Note: Power = Energy/time

From the question, P = 742/30 = 24.733 W. and I = 7 A.

Substitute these values into equation 4

V = 24.733/7

V = 3.53 V

Hence the potential drop across the conductor = 3.53 V