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Question: Answered & Verified by Expert
A battery of emf 12 V and internal resistance 2 Ω is connected in series with a tangent galvanometer of resistance 4 Ω. The deflection is 60o when the plane of the coil is along the magnetic meridian. To get a deflection of 30o, the resistance to be connected in series with the tangent galvanometer is
PhysicsExperimental PhysicsNEET
Options:
  • A 12 Ω
  • B 20 Ω
  • C 10 Ω
  • D 5 Ω
Solution:
1695 Upvotes Verified Answer
The correct answer is: 12 Ω
I=ktanθ,k being reduction factor and I1R

  R+rR+r+R=tanθtanθ

   4+26+R=tan30otan60o

  R=12 Ω

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