JEE Main 2019PhysicsCurrent ElectricityMediumMCQ

JEE Main 2019 — Current Electricity Question with Solution

JEE Main 2019 (08 Apr Shift 2)

Question

In the circuit shown, a four-wire potentiometer is made of a 400 cm long wire, which extends between A and B . The resistance per unit length of the potentiometer wire is r=0.01 Ω/cm. If an ideal voltmeter is connected as shown with jockey J  at 50 cm from end A , the expected reading of the voltmeter will be:

Choose an option

Show full solutionCorrect option: B
Correct answer
B0.25 V

Step-by-step explanation

From the given question we take, 

Current in the wire, I=VR=1.5+1.50.5+0.5+1+0.01×400=0.5 A

Resistance of 50 cm long wire, =50×0.01=0.5 Ω

Reading =  Current × Resistance
=0.5×0.5
=0.25 V

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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.