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A point charge q1 is held stationary at ...

A point charge `q_1` is held stationary at the origin. A second charge `q_2` is placed at a point a, and the electric potential energy of the pair of charges is `-6.4 xx 10^-8 J`. When the second charge is moved to point b, the electric force on the charge does `4.2 xx 10^-8 J` of work. What is the electric potential energy of the pair of charges when the second charge is at point b?

A

`-10.6xx10^-8J`

B

`-1.06xx10^-8J`

C

`-100.6xx10^-8J`

D

`-1.006xx10^-8J`

Text Solution

Verified by Experts

The correct Answer is:
A
Work done by electrostatic forces
`W=-/_\U=U_i-U_f`
`:. U_f=U_i-W`
`=(-6.4xx10^-8)-(4.2xx10^-8)`
`=-10.6xx10^-8J`
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Knowledge Check

  • When the separation between two charges is increase the electric potential energy of the charges.

    A
    increases
    B
    decreases
    C
    remains the same.
    D
    may increase or decrease

  • When the separation between two charges is increased, the electric potential energy of the charges

    A
    Increases
    B
    Decreases
    C
    May increases or decrease
    D
    Remains constant

  • Two point charges q each are fixed at (a,0) and (-a,0). A third charge Q is placed at origin. Electrons potential energy of the system will

    A
    increase if `Q` is slightly displaced along x-axis
    B
    decrease if Q is slightly displaced along x-axis
    C
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    D
    decrease if Q is slightly displaced along y-axis