Practice portal › Alternating Current › Resonance in Series LCR

Statement I: When the frequency of an a.c. source in a series LCR circuit increases, the current first increases, attains a maximum and then decreases. Statement II: In a series LCR circuit the power factor at resonance is one. Choose the correct option.

Asked in JEE Main 12th April 1st Shift 2023 · Power and bandwidth at resonance

• (1) Statement I is incorrect but Statement II is true
• (2) Both Statement I and Statement II are true
• (3) Statement I is correct but Statement II is false
• (4) Both Statement I and Statement II are false

Step-by-step solution

Why the other options are wrong

• (1) Rejects I, but the current does peak at resonance as frequency is swept.
• (3) Rejects II, but at resonance Z=R gives cos φ=1.
• (4) Rejects both correct statements.

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