The potential energy of the system of two identically charged spheres as shown in the figure is equal to (Assume the charge distribution to be uniform)
Answer & explanation
Correct answer: option 1
Each of the charged sphere will have potential energy due to its own charge
$U_1=\frac{1}{8 \pi \varepsilon_0} \frac{q^2}{r}$
The potential energy stored in one sphere due to the potential of the other is
$U_2=\frac{1}{4 \pi \varepsilon_0} \frac{q^2}{R}$
Therefore the P.E. stored in the system of spheres is
U = U1 + U2
$=\frac{1}{4 \pi \varepsilon_0}\left[\frac{1}{R}+\frac{1}{r}\right]$
∴ (A)