Answer to Question #206985 in Electric Circuits for nave

Question

A lamp is operated for 20 seconds with a current of 10A which supplies 400J of energy.

a) How much charge flows through the lamp?

b) How much energy each coulomb of charge transfer to the lamp?

c) Calculate the potential difference across the lamp.

Answer 1

Solution:

Given:

Current, I = 10 A, time, t = 20 s , energy, E = 400 J

Formula used:

Charge , q = Current x time

Energy, E = V I t

(a) The charge is given by

q = 10 x 20 = 200 C

(b) Energy of 200 C is 400J

So, energy by 1 coulomb = $\frac{400}{200}= 2 J$

(c) E = V I t

400 = V x 10 x 20

V = 2 V