MHT CET202522 Apr 2025Evening ShiftPhysicsCapacitanceActual
Earth is assumed to be a charged conducting sphere having volume V and surface area A . The capacitance of the earth in free space is ( ₀= permittivity of free space)
Options
- A2 ₀ V A
- B8 ₀ V A
- C12 ₀ V A
- D4 ₀ V A
Correct answer
C. 12 ₀ V A
Step-by-step solution
The capacitance of an isolated conducting sphere is C = 4 ₀ R , while its volume and surface area are V = 4 3 R^3 and A = 4 R^2 respectively. Eliminating the radius via V/A = 1 3 R yields R = 3V/A . Substituting into the capacitance formula gives C = 4 ₀ (3V/A) = 12 ₀ V/A , matching option C.