Page 12 - Electrostatics-11

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1 1
= − ∫
4 0 2 2

1
= − ∫ −2
4 0 2

−2+1 1
= − [ ]
4 0 −2 + 1 2

1 1
= − [ − ]
4 0 1 2

− 1
2
= − [ ]
4 0 . 2
1
By definition, this work done is electric potential difference (V).
− 1
2
∴ = − [ ]
4 0 . 2
1

This is the required expression for electric potential difference between points A
and B.

Electric potential at a point due to number of charges:

Electric potential at a point due to the number of charges is the sum of electric

potentials due to individual charges.

P

rn
r1

r3 Qn
r2

Q1
Q3

Q2

V = V1 + V2+ V3+ ... ... ... + Vn

11 Electrostatics