Which of the following combinations should be selected for better tuning of an LCR circuit used for…

Which of the following combinations should be selected for better tuning of an LCR circuit used for communication?
  1. R=20 Ω, L=1.5 H, C=35 μF
  2. R=25 Ω, L=2.5 H, C=45 μF
  3. R=15 Ω, L=3.5 H, C=30 μF
  4. R=25 Ω, L=1.5 H, C=45 μF

Solution

Quality factor is defined at resonance, when, inductive reactance is equal to the capacitive reactance.

It is defined as the ratio of voltage across the inductor or the capacitor and applied voltage or voltage across the resistor.

At resonance, impedance is equal to pure resistance, then, applied voltage and current are in phase.

Hence, the current is maximum.

Q=1RLC.

Q factor should be high.

 

 

Asked in: NEET 2016 (Phase 2)

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