MHT CET20243 May 2024Morning ShiftPhysicsCapacitanceActual
Two circular metal plates each of radius ' r ' are kept parallel to each other distance 'd' apart. The capacitance of the capacitor formed is ' C ₁ '. If the radius of each of the plates is increased to 2 times the earlier radius and their distance of separation decreased to half the initial value, the capacitance now becomes ' C ₂ '. The ratio of the capacitances C ₁: C ₂ . is
Options
- A1: 1
- B1: 2
- C1: 4
- D4: 1
Correct answer
C. 1: 4
Step-by-step solution
For the 1^ st capacitor, C ₁= ₀ ~A ₁ ~d = ₀ r ^2 ~d For the 2^ nd capacitor, aligned & C ₂= ₀ ~A ₂ ~d = ₀ 2 r ^2 d 2 = ₀ 4 r ^2 ~d =4 C ₁ & C ₁ C ₂ = C ₁ 4 C ₁ = 1 4 aligned