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Question: Answered & Verified by Expert
A meter bridge circuit is powered by an ideal battery of emf 5 V and negligible internal resistance. The bridge wire has a resistance per unit length equal to 0.1 Ω cm-1. Unknown resistance X is connected in the left gap and Ω in the right gap. The null point divides the wire in the ratio 2:3. What is the current (in A) drawn from the battery?
PhysicsCurrent ElectricityJEE Main
Solution:
1170 Upvotes Verified Answer
The correct answer is: 1
l1l2=23=v1v2

Now v1+v2=v=5 V =IR

For potentiometer wire R1R2=l1l2=23

x6=23xl=4 Ωm

The resistance per unit length of the wire is 0.1Ωcm=1Ωm

 x+1=Reff=5

 i=VReff=55=1 A

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