NTA Abhyas JEE Main2020PhysicsCurrent ElectricityPractice
When a battery of emf 8 V with internal resistance 0.5 Ω is charged by a 120 V DC supply using a series resistance of 15.5 Ω , then the terminal voltage of the battery is
Options
- A11 . 5   V
- B20 V
- C21 . 5 V
- D12 . 3 V
Correct answer
A. 11 . 5   V
Step-by-step solution
Here, emf of the battery = 8   V The internal resistance of the battery, r = 0.5   Ω The voltage of D. C supply = 120   V External resistance, R = 15.5   Ω When the battery of emf 8   V is charged from a DC supply of 120   V , the effective emf in the circular is ε = 120 - 8 = 112   V The total resistance of the circuit = R + r     = 15.5 + 0.5   Ω = 16   Ω ∴       Current in the circuit during charging I = ε R