JEE Main · PhysicsHard
In a series LCR circuit, the power factor is at a frequency and at a frequency . If the frequency is changed to , the power factor becomes again. The relationship between the frequencies is given by which of the following?
- A.
- B.
- C.
- D.
Show correct answer & step-by-step solution
Correct answer: B —
Solution
- The power factor is .
- For the same power factor at and , the magnitude of the reactance must be equal: .
- This implies .
- Since the resonant frequency is , we have .
- Hence the answer is (B).
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