Question

A $10\,V$ battery with internal resistance $1 \, \Omega$ and a $15\,V$ battery with internal resistance $0.6\,\Omega$ are connected in parallel to a voltmeter (see figure). The reading in the voltmeter will be close to :

• A. 11.9 V
• B. 12.5 V
• C. 13.1 V
• D. 24.5 V

Answer 1

Answer: (C)

$i=\frac{15-10}{1.6}=\frac{50}{16}$
(V) reads $15-i(0.6)=15-\left(\frac{50}{16} \times \frac{3}{5}\right)=15-\frac{15}{8}=15 \times \frac{7}{8}=13.1\, V$