Reactance, impedance and LCR series resonance - One Line Questions
1.
At resonance, the power factor of a series LCR circuit is: —
1
2.
What is the resonant frequency of an LC circuit? —
1/(2πLC)
3.
If L = 2 H, C = 8 μF, and R = 10 Ω, calculate the resonant angular frequency (ω0). —
250 rad/s
4.
In a series LCR circuit, the voltage across the inductor leads the current by: —
90 degrees
5.
In a series LCR circuit, the voltage across the capacitor lags the current by: —
90 degrees
6.
A high Q-factor in a resonance circuit indicates: —
A sharp resonance curve with a narrow bandwidth
7.
In an AC circuit, what does 'ω' represent? —
Angular frequency
8.
If the frequency of the AC source is increased above the resonant frequency in a series LCR circuit, the circuit behaves: —
Inductively
9.
If the frequency of the AC source is decreased below the resonant frequency in a series LCR circuit, the circuit behaves: —
Capacitively
10.
What is the condition for resonance in terms of frequency (f)? —
f = 1 / (2π * sqrt(LC))
11.
The resonant frequency (f0) of a series LCR circuit is related to the resonant angular frequency (ω0) by: —
f0 = ω0 / (2π)
12.
What is the unit of reactance in the SI system? —
Ohm (Ω)
13.
What is the unit of capacitance (C) in the SI system? —
Farad (F)
14.
If a capacitor is added in series to a resonant RLC circuit, what happens to the resonant frequency? —
Remains the same
15.
If an inductor is added in series to a resonant RLC circuit, what happens to the resonant frequency? —
Remains the same
16.
If the resistance in a series LCR circuit is increased, the sharpness of the resonance curve: —
Decreases
17.
If the frequency of the AC source is very low (approaching zero), a series LCR circuit behaves predominantly as: —
Capacitive
18.
If the frequency of the AC source is very high (approaching infinity), a series LCR circuit behaves predominantly as: —
Inductive
19.
The quantity 1/(ωC) is known as: —
Capacitive reactance
20.
The quantity ωL is known as: —
Inductive reactance
21.
In a series LCR circuit, if the frequency of the source is doubled, how does the inductive reactance change? —
It is doubled
22.
In a series LCR circuit, if the frequency of the source is doubled, how does the capacitive reactance change? —
It is halved
23.
The impedance of a series RLC circuit is Z = sqrt(R^2 + (ωL - 1/(ωC))^2). At resonance, the term (ωL - 1/(ωC)) becomes: —
Minimum (Zero)
24.
In a series LCR circuit, the impedance is minimum at resonance. This means the current will be: —
Maximum
25.
Which phenomenon is utilized in tuning a radio receiver? —
Electrical resonance
26.
What is the unit of power factor? —
Dimensionless
27.
Which of the following is NOT a unit of impedance or reactance? —
Watt
28.
What is the unit of inductance (L) in the SI system? —
Henry (H)
29.
In a series LCR circuit, if R = 0, then at resonance, the impedance Z is: —
Zero
30.
The quality factor (Q) of a series resonance circuit is defined as: —
(ω0L) / R
31.
In a series LCR circuit at resonance, the current is determined by: —
R only
32.
The impedance of a purely inductive circuit is called: —
Inductive reactance
33.
The impedance of a purely capacitive circuit is called: —
Capacitive reactance
34.
Which component in an AC circuit primarily causes inductive reactance? —
Inductor
35.
Which component in an AC circuit primarily causes capacitive reactance? —
Capacitor
36.
For a given L and C, the resonant frequency is inversely proportional to: —
sqrt(LC)
37.
What is the significance of resonance in a series LCR circuit? —
The current is maximum for a given voltage
38.
In a series LCR circuit, the voltage across the resistor is in phase with: —
The current
39.
What is impedance (Z) in an AC circuit? —
The total opposition to current flow, including resistance and reactance
40.
What is the formula for capacitive reactance (XC)? —
XC = 1 / (ωC)
41.
The impedance of a circuit is given by Z = sqrt(R^2 + X^2), where X is the net reactance. What is X? —
XL - XC
42.
What is the formula for inductive reactance (XL)? —
XL = ωL
43.
At resonance in a series LCR circuit, what is the relationship between inductive reactance (XL) and capacitive reactance (XC)? —
XL = XC
44.
At resonance, what is the value of the impedance (Z) in a series LCR circuit? —
Z = R
45.
How is impedance (Z) related to resistance (R), inductive reactance (XL), and capacitive reactance (XC) in a series LCR circuit? —
Z = sqrt(R^2 + (XL - XC)^2)
46.
What is the phase difference between voltage across the inductor and current through it in an AC circuit? —
π/2 (90 degrees) leading
47.
What is the phase difference between voltage across the capacitor and current through it in an AC circuit? —
π/2 (90 degrees) lagging
48.
In a series LCR circuit, resonance occurs when the phase angle between the applied voltage and the current is: —
0
49.
What is the condition for resonance in a series LCR circuit in terms of angular frequency (ω)? —
ω = 1 / sqrt(LC)
50.
The bandwidth (Δω) of a series resonance circuit is given by: —
ω0 / Q