JEE Main 2019PhysicsCurrent ElectricityHardMCQ

JEE Main 2019 — Current Electricity Question with Solution

JEE Main 2019 (12 Jan Shift 1)

Question

The galvanometer deflection, when key K1 is closed but K2 is open, equals θ0 (see figure). On closing K2 also and adjusting R2 to 5Ω, the deflection in galvanometer becomes θ05. The resistance of the galvanometer is, then, given by [Neglect the internal resistance of battery]:

Choose an option

Show full solutionCorrect option: B
Correct answer
B22 Ω

Step-by-step explanation

θ​0∝iG⇒θ​0C=iG

I-case Cθ0=V220+R ......(i)

II-case Cθ05=V220+5R5+R×55+R ....(ii)

From (i) and (ii) R=22Ω

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About this question

This is a previous-year question from JEE Main 2019, 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.