Read the following paragraph and answer the questions:
Total amount of work done in bringing the different charges to their respective positions from infinitely large mutual separation is defined as Electrostatic potential energy of a system.
Work done in carrying charge to any point from infinity is product of potential and charge:
W Potential `xx` Charge
This work is stored in the system of two point charges in the form of electrostatic potential energy U of the system.

What is the potential energy of the system when two charges of `1muC` are kept in air at 1 m apart:

Options

A. 1 eV
B. 1 J
C. `9xx10^(-3)J`
D. zero

Answer

C

Explanation

`9xx10^(-3)J`
Explanation: Electric potential energy of the system,
`U=(1)/(4piepsi_(0))=(q_(1)q_(2))/(r)`
Here, `q_(1)=q_(2)=1muC=1xx10^(-6)C`
r=1 m and `(1)/(4piepsi_(0))`
`=9xx10^(9)(Nm^(2))/(C^(2))`
`:.U=(9xx10^(9)xx1xx10^(-6)xx1xx10^(-6))/(1)`
`=9xx10^(-3)J`