In the given circuit, an ideal voltmeter connected across the 10 Ω resistance reads 2V. The internal resistance r, of each cell is: (a) 1.5 Ω (b) 1 Ω (c) 0.5 Ω (d) 0 Ω

Answer: (c). 15 Ω ∥ 10 Ω = 6 Ω; voltmeter reads 2 V across this pair. Circuit current I = 2/6 = 1/3 A I = (1.5 + 1.5)/(6 + 2 + 2r) ⇒ 1/3 = (3)/(8 + 2r) ⇒ 8 + 2r = 9 r = 0.5 Ω. So the answer is (c).

In the given circuit, an ideal voltmeter connected across the 10 Ω… | JEE Main 2019 (10 Apr, Shift 1)

Q34JEE Main 2019 · 10 APR · SHIFT 1Medium

Cells: EMF, Internal Resistance & Combinations

In the given circuit, an ideal voltmeter connected across the 10 $\Omega$ resistance reads 2V. The internal resistance r, of each cell is:

Show answer and solution

Answer: (c)

$15\ \Omega \parallel 10\ \Omega = 6\ \Omega$ ; voltmeter reads 2 V across this pair.
Circuit current $I = \frac{2}{6} = \frac{1}{3}\text{ A}$
$I = \frac{1.5 + 1.5}{6 + 2 + 2r} \Rightarrow \frac{1}{3} = \frac{3}{8 + 2r} \Rightarrow 8 + 2r = 9$
$r = 0.5\ \Omega$ . So the answer is (c).

Report a mistake

Cells: EMF, Internal Resistance & Combinations question from JEE Main 2019 (10 Apr, Shift 1)

More questions on Cells: EMF, Internal Resistance & Combinations