JEE Main 2015PhysicsAlternating CurrentMediumMCQ

JEE Main 2015 — Alternating Current Question with Solution

JEE Main 2015 (11 Apr Online)

Question

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:

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Show full solutionCorrect option: A
Correct answer
AParallel with C and has a magnitude 1-ω2LCω2L

Step-by-step explanation



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=1ωCeq⇒Ceq=1ω2L

⇒C+C′=1ω2L⇒C′=1ω2L-C

⇒C′=1-ω2LCω2L

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About this question

This is a previous-year question from JEE Main 2015, covering the Alternating Current 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.