In a potentiometer experiment, the balancing with a cell is at length 240 cm. On shunting the cell with a resistance of 2\ , the balancing length becomes 120 cm. The internal resistance of the cell is

Correct answer: D. 2\ The internal resistance r of a cell determined using a potentiometer is given by the formula: r = R ( (l_1)/(l_2) - 1 ) Given l_1 = 240 cm, l_2 = 120 cm, and R = 2\ . Substituting the values: r = 2 ( (240)/(120) -1 ) r = 2 (2 - 1) r = 2\ Answer: 2\

MHT CET 202623 AprilMorning Shift

Exam: MHT CET
Year: 2026
Date: 23 April
Shift: Morning Shift
Subject: Physics
Chapter: Current Electricity

MHT CET 2026 · 23 April · Morning Shift · Physics · Current Electricity

In a potentiometer experiment, the balancing with a cell is at...

In a potentiometer experiment, the balancing with a cell is at length

240

cm. On shunting the cell with a resistance of

2\ \Omega

, the balancing length becomes

120

cm. The internal resistance of the cell is

Options

A $1\ \Omega$
B $0.5\ \Omega$
C $4\ \Omega$
D $2\ \Omega$

Correct answer

D. $2\ \Omega$

Step-by-step solution

The internal resistance

r

of a cell determined using a potentiometer is given by the formula:

r = R \left( \dfrac{l_1}{l_2} -

1 \right)

<br><br>Given

l_1 = 240

cm,

l_2 = 120

cm, and

R = 2\ \Omega

.<br><br>Substituting the values:<br><br>

r = 2 \left( \dfrac{240}{120} -1 \right)

<br><br>

r = 2 (2 - 1)

<br><br>

r = 2\ \Omega

<br><br>Answer:

2\ \Omega

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