The spheres shown in the figure are connected by a conductor. The capacitance of the system is
Answer & explanation
Correct answer: option 3
As there will be no charge on the inner sphere, therefore the capacitance only will exist due to outer sphere.
Hence the capacitance of the system is the capacitance due to outer sphere of radius b,
therefore C = $4 \pi \varepsilon_0 b$.
∴ (C) is correct