JEE Main201910 Apr 2019Morning ShiftPhysicsCurrent ElectricityActual
In the given circuit, an ideal voltmeter connected across the 10 Ω resistance reads 2 V . The internal resistance r , of each cell is:
Options
- A0 Ω
- B1.5 Ω
- C0.5 Ω
- D1 Ω
Correct answer
C. 0.5 Ω
Step-by-step solution
Current through battery = 2 10 + 2 15 = 6 + 4 30 = 1 3 A Also, net resistance R e q = 15 × 10 15 + 10 + 2 + 2 r = 8 + 2 r ⇒ 1 3 = 1.5 + 1.5 8 + 2 r 8 + 2 r = 9 r = 1 2 = 0.5   Ω