Question

Two identical cells each of emf 1.5 V are connected in parallel across a parallel combination of two resistors each of resistance 20 W. A voltmeter connected in the circuit measures 1.2 V. The internal resistance of each cell is

• A. 2.5 W
• B. 4 W
• C. 5 W
• D. 10 W

Answer 1

Answer: (C)

5 W

Answer 2

$\frac{1.5×10}{10+\frac{r}{2}}$=1.2
⇒r=5Ω
The correct option is (C) : 5 W