To measure the internal resistance of a battery, potentiometer is used. For R=10 , the balance point is observed at l=500 ~cm and for R=1 the balance point is observed at l=400 ~cm . The internal resistance of the

Correct answer: B. 0.3 Let potential gradient be λ . aligned & i × 10=λ × 500= -ir_ s & 500 λ= -50 λ r_ s aligned Also, aligned & i^ × 1=λ × 400= -i^ r_ s & 400 λ= -400 λ r_5 & 100 λ=350 λ r_ s r_ s =(10)/(35) 0.3 aligned

JEE Main 20244 AprilMorning Shift

Exam: JEE Main
Year: 2024
Date: 4 April
Shift: Morning Shift
Subject: Physics
Chapter: Current Electricity

JEE Main 2024 · 4 April · Morning Shift · Physics · Current Electricity

To measure the internal resistance of a battery, potentiometer is...

To measure the internal resistance of a battery, potentiometer is used. For

\mathrm{R}=10 \Omega

, the balance point is observed at

l=500 \mathrm{~cm}

and for

\mathrm{R}=1 \Omega

the balance point is observed at

l=400 \mathrm{~cm}

. The internal resistance of the battery is approximately :

Options

A $0.2 \Omega$
B $0.3 \Omega$
C $0.4 \Omega$
D $0.1 \Omega$

Correct answer

B. $0.3 \Omega$

Step-by-step solution

Let potential gradient be

\lambda

\begin{aligned} & \therefore \mathrm{i} \times 10=\lambda \times 500=\varepsilon-\mathrm{ir}_{\mathrm{s}} \\ & \Rightarrow 500 \lambda=\varepsilon-50 \lambda \mathrm{r}_{\mathrm{s}} \end{aligned}

Also,

\begin{aligned} & \mathrm{i}^{\prime} \times 1=\lambda \times 400=\varepsilon-\mathrm{i}^{\prime} \mathrm{r}_{\mathrm{s}} \\ & \Rightarrow 400 \lambda=\varepsilon-400 \lambda \mathrm{r}_5 \\ & \therefore 100 \lambda=350 \lambda \mathrm{r}_{\mathrm{s}} \Rightarrow \mathrm{r}_{\mathrm{s}}=\frac{10}{35} \approx 0.3 \Omega \end{aligned}

Practice Current Electricity on Quantrex Academy →

More from Current Electricity

A metal wire of cross-sectional area 0.5 mm ^2 and length 100 m is connected across a… JEE Advanced 2026 As shown in the figure, the resistance of a galvanometer G can be found by the… JEE Advanced 2026 The stored charge in the capacitor in steady state of the following circuit is ________ μ… JEE Main 2026 A moving coil of galvanometer when shunted with 2\,Ω resistance gives a full scale… JEE Main 2026 Two cells of emfs 1 V and 2 V and internal resistance 2\,Ω and 1\,Ω , respectively… JEE Main 2026 Refer to the circuit diagram given below. The heat generated across the 6\,Ω resistance… JEE Main 2026 In an experiment to determine the resistance of a given wire using Ohm's law, the… JEE Main 2026 Under steady state condition the potential difference across the capacitor in the circuit… JEE Main 2026 Full Current Electricity list All JEE Main PYQs