Question

The work done on a 2.0 coulomb bead, and hence its electric potential energy at point A, was 20 joules. A new bead carries twice as much charge, 4.0 coulombs. Intuitively, how much electric potential energy do you expect the new bead to have at point A? Why?

Answer 1

40 J

Step-by-step explanation:

q = magnitude of charge on the old bead = 2.0 C

U = Electric potential energy of old bead at point A = 20 Joules

V = Electric potential at A

Electric potential energy is given as

U = q V

20 = (2.0)V

V = 10 volts

Electric potential at point A remains unchanged when new bead of charge 4.0 C is placed there

q' = magnitude of charge on new bead = 4.0 C

V = Electric potential at A = 10 volts

U' = Electric potential energy of new bead at point A

U' = q' V

U' = (4.0) (10)

U' = 40 J