JEE PYQ: Current Electricity Question 47
Question 47 - 2019 (10 Apr 2019 Shift 1)
In the given circuit, an ideal voltmeter connected across the $10,\Omega$ resistance reads 2V. The internal resistance r, of each cell is:
(1) $1,\Omega$
(2) $0.5,\Omega$
(3) $1.5,\Omega$
(4) $0,\Omega$
Show Answer
Answer: (2)
Solution
Voltage across $10,\Omega$ is 2V, so $i \times 6 = 2$ (since $10,\Omega$ is in parallel with $15,\Omega$ giving $6,\Omega$). $i = \frac{3}{8+2r}$. $i \times 6 = \frac{3 \times 6}{8+2r} = 2$. $9 = 8 + 2r$. $r = 0.5,\Omega$.
BETA
