The electric potential energy of the pair of charges when the second charge is at point b is U at b = +7.3×10⁻⁸J.
Electric potential is the amount of work done in moving point charge from infinity to aspecific point.
Calculation of the electric potential energy:
Here the particle should be moved from the point at the time when the potential energy should be U a
The U b should be the change in the potential energy
W is work done.
(W at a )-(W at b) = U a - U b
U b = U a - (W at a )+(W at b)
So,
= 5.4 × 10⁻⁸J - ( -1.9×10⁻⁸ J)
= +7.3×10⁻⁸J.
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