Question

Two charges of magnitude `5 nC and -2 nC` are placed at points (2cm,0,0) and (x cm,0,0) in a region of space. Where there is no other external field. If the electrostatic potential energy of the system is `-0.5 muJ`. What is the value of x ?
A. 20 cm
B. 80 cm
C. 4 cm
D. 16 cm

Answer 1

Correct Answer - A
Potential energy of system `U=1/(4piepsilon_0)(q_1q_2)/r`
`=0.5xx10^(-6)=(9xx10^(9)xx5xx10^(-9)xx(-2)xx10^(-9))/((x-2)xx10^(-2))`
`rArr` x =20 cm