Question

A charge 10 e.s.u. is placed at a distance of 2 cm from a charge 40 e.s.u. and 4 cm from another charge of 20 e.s.u. The potential energy of the charge 10 e.s.u. is (in ergs)

• A. 87.5
• B. 112.5
• C. 150
• D. 250

Answer 1

Answer: (D)

250

Answer 2

Potential energy of 10 e.s.u. charge is

$U = \frac{10 \times 40}{2} + \frac{10 \times 20}{4} = 250erg.$