Answer:
40 J
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
