21. Shape of the resonance curve depends upon the?

A. Q-factor
B. Voltage
C. Current
D. Either voltage or current

Answer: A

The shape of the resonance curve depends on the Q factor because of the equation:

Q = Resonance frequency / Bandwidth.

Sharp resonance means a high-quality factor.

22. A circuit is said to be selective if it has a _____ peak and ____ bandwidth.

A. Blunt, narrow
B. Sharp, narrow
C. Sharp, broad
D. Blunt, broad

Answer: B

For a circuit to be selective, it should have a high-quality factor. And we know that for high-quality factors, resonance frequency should be high(peak should be sharp) and bandwidth should be narrow.

23. What is the Q factor of a selective circuit?

A. Very low
B. Very high
C. Zero
D. Infinity

Answer: B

For a circuit to be selective, it should have a high-quality factor. It should have a sharp peak with narrow bandwidth.

24. In selective circuits, the higher the Q factor _________ the peak.

A. Sharper
B. Blunter
C. Neither sharper nor blunter
D. Either sharper or blunter

Answer: A

Q = Resonance frequency / Bandwidth.

Higher the quality factor, the sharper the peak of the resonance curve.

25. Q is a measure of _________

A. Resonance
B. Bandwidth
C. Selectivity
D. Either resonance or bandwidth

Answer: C

For a circuit to be selective, it should have a high-quality factor. It should have a sharp peak with narrow bandwidth.

26. In selective circuits, the resonant frequency lies in the ________ of the bandwidth frequency range.

A. Beginning
B. End
C. Midpoint
D. Cannot be determined

Answer: C

In selective circuits, the resonant frequency lies in the midpoint of the bandwidth frequency range.

27. In order for high selectivity, the resistance must be?

A. Small
B. Large
C. Negative
D. Positive

Answer: A

For high selectivity, the Q factor should be large and for the Q factor to be large, the resistance would be small because Q is inversely proportional to the resistance.

28. In a series RLC circuit, the phase difference between the voltage across the capacitor and the voltage across the resistor is?

A. 0°
B. 90°
C. 180°
D. 360°

Answer: B

In a series RLC circuit, the voltage across the capacitor lags the current by 90°, and the voltage across the resistor is in phase with the current so, the phase difference between the voltage across the capacitor and the voltage across the resistor is 90°.

29. In a series RLC circuit, the phase difference between the voltage across the inductor and the voltage across the resistor is?

A. 0°
B. 90°
C. 180°
D. 360°

Answer: B

In a series RLC circuit, the voltage across the inductor leads the current by 900 and the voltage across the resistor is in phase with the current so, the phase difference between the voltage across the inductor and the voltage across the resistor is 90°.

30. In a series RLC circuit, the phase difference between the voltage across the capacitor and the voltage across the inductor is?

A. 0°
B. 90°
C. 180°
D. 360°

Answer: C

In a series RLC circuit, the voltage across the inductor leads the current by 900, and the voltage across the capacitor lags the current by 90° so, the phase difference between the voltage across the inductor and the voltage across the capacitor is 180°.