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Two point charges +10μC and – 10μC are separated by a distance of 40 cm in air -
(i) Calculate the electrostatic potential energy of the system, assuming the zero of the potential energy
to be at infinity.
(ii) Draw an equipotential surface of the system.
(iii) How much work is required to separate the two charges infinitely away from each other ?

Dear Student,

Electrostatic Potential forcharges q1 and q2 = kq1q2r  where k=14πε0 ⇒9×109 

or V= 9×109×-10×10-6×10×10-60.4=-2.25 J

(ii) Equipotential surface will be a 



(iii)  Amount of work done to separate them and take to infinity is same as potential difference between them as there we try to bring these two charges from infinity to the vicinity of 0.4 m of each other.

Regards.

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View Full Answer
Hello Aditya dear, electrostatic potential energy = 1/4​πεo * Q1 * Q2 / r
In our problem Q1 = 10 * 10^-6 C and Q2 = - 10 * 10^-6 C
 1/4​πεo = 9 * 10^9 C^2 N^-1 m^-2
r = distance between = 0.40 m
Hope you would plug and get the required one in J
11) Equipotential surface will be the plane normal to the line joining Q1 and Q2 through its mid point
III) That amount which you have computed is needed to separate them infinitely far each other
 
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