JEE Main 2018 — Current Electricity Question with Solution
From: JEE Main 2018 (Offline)
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 , a balance is found when the cell is connected across 40 cm of the wire. Find the internal
resistance of the cell.
Choose an option
Show full solutionCorrect option: C
Correct answer
C1.5
Step-by-step explanation
Internal resistance of potentiometer,
r =
Initially when no current passes through the galvanometer then
emf, E = K (52)
here K = potential gradient
After cell is shunted by a resistance 5 , then,
Terminal voltage, V = K(40)
r = 5
= 5
= 1.5
r =
Initially when no current passes through the galvanometer then
emf, E = K (52)
here K = potential gradient
After cell is shunted by a resistance 5 , then,
Terminal voltage, V = K(40)
r = 5
= 5
= 1.5
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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.