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Question: Answered & Verified by Expert
For the LCR circuit, shown here, the current is observed to lead the applied voltage. An additional capacitor C , when joined with the capacitor C present in the circuit, makes the power factor of the circuit unity. The capacitor C , must have been connected in:
PhysicsAlternating CurrentJEE MainJEE Main 2015 (11 Apr Online)
Options:
  • A Parallel with C and has a magnitude 1-ω2LCω2L
  • B Series with C and has a magnitude 1-ω2LCω2L
  • C Series with C and has a magnitude Cω2LC-1
  • D Parallel with C and has a magnitude Cω2LC-1
Solution:
2908 Upvotes Verified Answer
The correct answer is: Parallel with C and has a magnitude 1-ω2LCω2L


Current is leading,  it means inductive reactance is more than capacitive reactance

For making power factor to be unity the value of C is to be increased.

another capacitor C should be connected in parallel. So in that condition XL=XC

ωL=1ωCeqCeq=1ω2L

C+C=1ω2LC=1ω2L-C

C=1-ω2LCω2L

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