Question

Two batteries, one of emf 18 volts and internal resistance $2\, \Omega$ and the other of emf 12 volts and internal resistance $1\, \Omega$ are connected as shown. The voltmeter V will record a reading of

• A. 30 volt
• B. 18 volt
• C. 15 volt
• D. 14 volt

Answer 1

Answer: (D)

14 volt

Answer 2

From Kirchhoff's law.
$I \times 2 + I \times 1 = 18 -12$
Current in the circuit,

$\, \, \, \, I=\frac{V}{R}=\frac{6}{3}=2 \, A$
Voltage drop across $2\, \Omega,$
$\, \, \, \, V_1 = 2 \times 2 = 4\, V$
Voltmeter reading $= 18 - 4 = 14\, V.$