JEE Main 2018PhysicsCurrent ElectricityMediumMCQ

JEE Main 2018 — Current Electricity Question with Solution

JEE Main 2018 (08 Apr)

Question

In a potentiometer experiment, it is found that no current passes through the galvanometer when the terminals of the cell are connected across 52 cm of the potentiometer wire. If the cell is shunted by a resistance of 5 Ω ,a balance is found when the cell is connected across 40 cm of the wire. Find the internal resistance of the cell.

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Show full solutionCorrect option: C
Correct answer
C1.5 Ω

Step-by-step explanation

Without shunting conditions, 



Es=52×x  .....(i), when, balanced, where, x= potential gradient of wire, with shunting condition



On balancing, Es-Er+Rr=40×x  ....(ii).
On solving:
(i)(ii)⇒11-rr+R=5240
∴r=1.5 Ω

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About this question

This is a previous-year question from JEE Main 2018, covering the Current Electricity chapter of Physics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.