JEE Main · 2023 · 29 Jan 2023 · Shift 2 · Alternating Current

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For the given figures, choose the correct options:
Structure a
a
Structure b
b
  1. (A)The rms current in circuit (b) can never be larger than that in (a)✓ Correct
  2. (B)The rms current in figure (a) is always equal to that in figure (b)
  3. (C)The rms current in circuit (b) can be larger than that in (a)
  4. (D)At resonance, current in (b) is less than that in (a)

Answer: (A)

Solution

In the first circuit the source drives current through a resistor alone, so the current is simply . In the second circuit the same resistor is in series with an inductor and a capacitor, and the impedance is never smaller than , dropping to only at resonance when . Since the current is , the second circuit can at best match the first and can never carry a larger rms current than the purely resistive one.

JEE Main · 2023 · 29 Jan 2023 · Shift 2 · Single correct option

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