Two charges q1 and q2 are placed 30 cm apart as shown in the figure. A third charge q3is moved along the arc of a circle of radius 40 cm from C to D. The change in the potential energy of the system is q34πϵ0k, where k is
Options:
A .  8q2
B .  8q1
C .  6q2
D .  6q1
Answer: Option A : A Change in potential energy (ΔU)=Uf−Ui ⇒ΔU=14πϵ0[(q1q30.4+q2q30.1)−(q1q30.4+q2q30.5)] ⇒ΔU=14πϵ0[8q2q3]=q34πϵ0(8q2) ∴k=8q2
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