Two small insulating spheres carry charges and (unknown)

PHYSICS · Single correct · CBSE · Physics · Electrostatic Potential and Capacitance · Electrostatic Potential and Capacitance

Problem

Two small insulating spheres carry charges

q_1 = +4.0\,\mu\text{C}

and

q_2

(unknown). They are released from rest

r_0 = 0.25\,\text{m}

apart but cannot approach closer than

r_f = 0.020\,\text{m}

because of their physical size. Exactly

5.0\,\text{J}

of electric potential energy is converted into kinetic energy as they move from

r_0

r_f

. What is

q_2

? (a)

+3.0\,\mu\text{C}

(b)

-0.30\,\mu\text{C}

(c)

-3.0\,\mu\text{C}

(d)

-32\,\mu\text{C}