Current Electricity

JEE Main level, single correct, medium

43 of 380

Question 43 of 380

Two sources of equal emf are connected to an external resistance R. The internal resistance of the two sources are R1R_1 and R2(R2>R1)R_2\left(R_2\gt R_1\right). If the potential difference across the source having internal resistance R2\mathrm{R}_2 is zero, then

Show answer and solution

Answer: (B) R=R2−R1\mathrm{R}=\mathrm{R}_2-\mathrm{R}_1

I=2ER1+R2+R\mathrm{I}=\frac{2 \mathrm{E}}{\mathrm{R}_1+\mathrm{R}_2+\mathrm{R}}
E−R2I=0\mathrm{E}-\mathrm{R}_2 \mathrm{I}=0
⇒R=R2−R1\Rightarrow \mathrm{R}=\mathrm{R}_2-\mathrm{R}_1

JEE Main question paper PDF

Open a shift to read the full paper on this page, or download it.

JEE Main 2025 Apr 2 Shift 1 question paper

Open Download PDF

Opening paper…

Explain it as a whiteboard videoStep-by-step, in Hinglish or English. Your first video needs no login.Solved it on paper but got it wrong?Upload a photo of your working. Mistake Doctor marks the exact line that broke.
See it move: Circuit builder simulationDrag the sliders and watch the numbers in this question change.Revise Current Electricity firstFormula sheet, solved examples and the traps students fall into.

More Physics practice

JEE Main Physics practice question on Current Electricity (Electric Current and Drift of Electrons), with the answer and a step-by-step solution. Scan a question from your own book or paper to get a whiteboard video.