JEE Main2015PhysicsCurrent ElectricityActual
A 10   V battery with internal resistance 1   Ω and a 15   V battery with internal resistance 0.6 Ω are connected in parallel to a voltmeter (see figure). The reading in the voltmeter will be close to:
Options
- A11.9 V
- B13.1 V
- C12.5 V
- D24.5 V
Correct answer
B. 13.1 V
Step-by-step solution
The equivalent emf of the battery parallel combination is given as Equation =   E 1 r 1     +   E 2 r 2 1 r 1   +   1 r 2 =   10 1   +   15 0.6 1   1   +   1   0.6 =   10 +   150 6 1 +   10 6   = 105 8 = 13.1   V ∴       The reading measured by voltmeter = 13.1   V