AP EAMCET202120 Aug 2021Morning ShiftPhysicsCapacitanceActual
A 60 μF parallel plate capacitor whose plates are separated by 6 mm is charged to 250 V , and then the charging source is removed. When a slab of dielectric constant 5 and thickness 3 mm is placed between the plates, find the change in the potential difference across the capacitor?
Options
- A250   V
- B100   V
- C150   V
- D75   V
Correct answer
B. 100   V
Step-by-step solution
Capacitance of capacitor after inserting a slab of dielectric constant 5   and of thickness t = 3   mm is, C ' = C 1 1 - t d + t k d ⇒ C ' = 12   μF 1 1 - 3   mm 6   mm + 3   mm 5 × 6   mm = 12   μF × 20 12 ⇒ C ' = 20   μF Now, after removing the charging source from the capacitor the charge remain same, q = C V = C ' V ' ⇒ C V = C ' V ' ⇒ 12   μF × 250   V = 20   μ