AC Circuits
Q. In an AC circuit, if the frequency is 60Hz and the inductance is 0.2H, what is the inductive reactance? (2021)
-
A.
12.56Ω
-
B.
37.68Ω
-
C.
75.36Ω
-
D.
100Ω
Solution
Inductive reactance (XL) = 2πfL = 2π(60)(0.2) ≈ 75.36Ω.
Correct Answer: B — 37.68Ω
Learn More →
Q. In an AC circuit, if the frequency is increased, what happens to the inductive reactance? (2020)
-
A.
It increases
-
B.
It decreases
-
C.
It remains constant
-
D.
It becomes zero
Solution
Inductive reactance (XL = 2πfL) increases with an increase in frequency.
Correct Answer: A — It increases
Learn More →
Q. In an AC circuit, if the power factor is 0.8, what is the angle between the voltage and current? (2020)
-
A.
36.87°
-
B.
53.13°
-
C.
60°
-
D.
45°
Solution
The angle θ can be found using cos(θ) = power factor. Therefore, θ = cos⁻¹(0.8) ≈ 36.87°.
Correct Answer: B — 53.13°
Learn More →
Q. In an AC circuit, if the resistance is 10 ohms and the inductive reactance is 20 ohms, what is the impedance? (2020)
-
A.
10 ohms
-
B.
20 ohms
-
C.
√(10² + 20²)
-
D.
30 ohms
Solution
The impedance Z = √(R² + XL²) = √(10² + 20²) = √(100 + 400) = √500 = 22.36 ohms.
Correct Answer: C — √(10² + 20²)
Learn More →
Q. In an AC circuit, if the resistance is 10 ohms and the inductive reactance is 20 ohms, what is the total impedance? (2020)
-
A.
10 ohms
-
B.
20 ohms
-
C.
√(10² + 20²)
-
D.
30 ohms
Solution
The total impedance Z = √(R² + XL²) = √(10² + 20²) = √(100 + 400) = √500 = 22.36 ohms.
Correct Answer: C — √(10² + 20²)
Learn More →
Q. In an AC circuit, if the resistance is 10Ω and the inductive reactance is 20Ω, what is the total impedance? (2020)
-
A.
10Ω
-
B.
20Ω
-
C.
√(10² + 20²)
-
D.
30Ω
Solution
The total impedance Z = √(R² + XL²) = √(10² + 20²) = √(100 + 400) = √500 = 22.36Ω.
Correct Answer: C — √(10² + 20²)
Learn More →
Q. In an AC circuit, if the voltage is 120 V and the current is 10 A with a power factor of 0.8, what is the real power consumed? (2021)
-
A.
960 W
-
B.
1200 W
-
C.
800 W
-
D.
1000 W
Solution
Real power P = V * I * power factor = 120 * 10 * 0.8 = 960 W.
Correct Answer: A — 960 W
Learn More →
Q. In an AC circuit, if the voltage is 120V and the current is 10A with a power factor of 0.8, what is the real power consumed? (2021)
-
A.
120W
-
B.
800W
-
C.
960W
-
D.
1000W
Solution
Real power P = V * I * power factor = 120V * 10A * 0.8 = 960W.
Correct Answer: C — 960W
Learn More →
Q. In an AC circuit, if the voltage is 120V and the current is 10A, what is the power factor if the real power is 600W? (2022)
-
A.
0.5
-
B.
0.6
-
C.
0.8
-
D.
1.0
Solution
Power factor = Real Power / (Voltage x Current) = 600 / (120 x 10) = 600 / 1200 = 0.5.
Correct Answer: B — 0.6
Learn More →
Q. In an AC circuit, if the voltage is given by V(t) = 100 sin(100t), what is the RMS voltage? (2023)
-
A.
100 V
-
B.
70.7 V
-
C.
50 V
-
D.
141.4 V
Solution
The RMS voltage is V_rms = V0/√2 = 100/√2 = 70.7 V.
Correct Answer: B — 70.7 V
Learn More →
Q. In an AC circuit, if the voltage is given by V(t) = 100√2 sin(1000t), what is the peak voltage? (2023)
-
A.
100 V
-
B.
100√2 V
-
C.
200 V
-
D.
50 V
Solution
The peak voltage is given by the coefficient of sin, which is 100√2.
Correct Answer: B — 100√2 V
Learn More →
Q. In an AC circuit, if the voltage is V(t) = 120 sin(ωt), what is the RMS voltage? (2017)
-
A.
120 V
-
B.
60 V
-
C.
84.85 V
-
D.
100 V
Solution
RMS voltage V_rms = V_peak / √2 = 120 / √2 = 84.85 V.
Correct Answer: C — 84.85 V
Learn More →
Q. In an AC circuit, the voltage is given by V(t) = V0 sin(ωt). What is the peak voltage if V0 = 10V? (2021)
-
A.
5V
-
B.
10V
-
C.
15V
-
D.
20V
Solution
The peak voltage V0 is given directly in the equation as 10V.
Correct Answer: B — 10V
Learn More →
Q. In an AC circuit, the voltage is given by V(t) = V0 sin(ωt). What is the peak voltage? (2021)
Solution
The peak voltage in the equation V(t) = V0 sin(ωt) is V0.
Correct Answer: A — V0
Learn More →
Q. In an RLC circuit, if the resistance is 6Ω, inductive reactance is 8Ω, and capacitive reactance is 4Ω, what is the total impedance? (2021)
-
A.
10Ω
-
B.
12Ω
-
C.
14Ω
-
D.
16Ω
Solution
Total impedance Z = √(R² + (XL - XC)²) = √(6² + (8 - 4)²) = √(36 + 16) = √52 ≈ 10Ω.
Correct Answer: B — 12Ω
Learn More →
Q. In an RLC circuit, if the resistance is increased, what happens to the quality factor (Q)? (2021)
-
A.
Increases
-
B.
Decreases
-
C.
Remains the same
-
D.
Becomes zero
Solution
The quality factor Q is inversely proportional to resistance. Increasing resistance decreases Q.
Correct Answer: B — Decreases
Learn More →
Q. In an RLC series circuit, if the inductive reactance is greater than the capacitive reactance, the circuit is said to be: (2022)
-
A.
Resonant
-
B.
Inductive
-
C.
Capacitive
-
D.
Purely resistive
Solution
If the inductive reactance (XL) is greater than the capacitive reactance (XC), the circuit is inductive.
Correct Answer: B — Inductive
Learn More →
Q. In an RLC series circuit, if the resistance is 10 Ω, inductance is 0.1 H, and capacitance is 100 μF, what is the resonant frequency? (2023)
-
A.
50 Hz
-
B.
100 Hz
-
C.
159 Hz
-
D.
200 Hz
Solution
The resonant frequency f0 = 1/(2π√(LC)) = 1/(2π√(0.1 * 100e-6)) = 159 Hz.
Correct Answer: C — 159 Hz
Learn More →
Q. In an RLC series circuit, if the total impedance is 50 ohms and the resistance is 30 ohms, what is the reactance? (2020)
-
A.
40 ohms
-
B.
30 ohms
-
C.
20 ohms
-
D.
10 ohms
Solution
Using Z = √(R² + X²), we find X = √(Z² - R²) = √(50² - 30²) = √(2500 - 900) = √1600 = 40 ohms.
Correct Answer: A — 40 ohms
Learn More →
Q. The resonant frequency of an RLC circuit is given by which formula? (2022)
-
A.
f = 1/(2π√(LC))
-
B.
f = 2π√(LC)
-
C.
f = LC
-
D.
f = R/(2πL)
Solution
The resonant frequency f of an RLC circuit is given by f = 1/(2π√(LC)).
Correct Answer: A — f = 1/(2π√(LC))
Learn More →
Q. What is the capacitive reactance of a capacitor of 10μF at a frequency of 60 Hz? (2016)
-
A.
265.26Ω
-
B.
159.15Ω
-
C.
100Ω
-
D.
50Ω
Solution
Capacitive reactance Xc = 1 / (2πfC) = 1 / (2π * 60 * 10e-6) = 265.26Ω.
Correct Answer: A — 265.26Ω
Learn More →
Q. What is the capacitive reactance of a capacitor with a capacitance of 10μF at a frequency of 50Hz? (2020)
-
A.
318.31 ohms
-
B.
159.15 ohms
-
C.
31.83 ohms
-
D.
15.92 ohms
Solution
Xc = 1 / (2πfC) = 1 / (2π × 50 × 10 × 10^-6) = 318.31 ohms.
Correct Answer: A — 318.31 ohms
Learn More →
Q. What is the effect of increasing the capacitance in a capacitive AC circuit on the current? (2022)
-
A.
Increases current
-
B.
Decreases current
-
C.
No effect
-
D.
Current becomes zero
Solution
Increasing capacitance increases the current in a capacitive AC circuit, as current I = V/Xc.
Correct Answer: A — Increases current
Learn More →
Q. What is the effect of increasing the frequency on the capacitive reactance in an AC circuit? (2022)
-
A.
Increases
-
B.
Decreases
-
C.
Remains the same
-
D.
Becomes zero
Solution
Capacitive reactance Xc = 1/(2πfC), so increasing frequency decreases Xc.
Correct Answer: B — Decreases
Learn More →
Q. What is the effect of increasing the frequency on the impedance of a capacitor? (2023)
-
A.
Increases
-
B.
Decreases
-
C.
Remains constant
-
D.
Becomes infinite
Solution
The impedance of a capacitor decreases with increasing frequency.
Correct Answer: B — Decreases
Learn More →
Q. What is the effect of increasing the frequency on the total impedance of an RLC circuit? (2020)
-
A.
It always increases
-
B.
It always decreases
-
C.
It can increase or decrease
-
D.
It remains constant
Solution
The total impedance can increase or decrease depending on the relationship between R, XL, and XC as frequency changes.
Correct Answer: C — It can increase or decrease
Learn More →
Q. What is the formula for calculating the total current in a parallel RLC circuit? (2023)
-
A.
I = V/R
-
B.
I = V/(1/R + 1/X)
-
C.
I = V/(R + X)
-
D.
I = V/R + V/X
Solution
In a parallel RLC circuit, the total current is calculated using I = V/(1/R + 1/X), where X is the total reactance.
Correct Answer: B — I = V/(1/R + 1/X)
Learn More →
Q. What is the formula for the average power consumed in an AC circuit with a phase angle φ? (2020)
-
A.
P = VI
-
B.
P = VI cos(φ)
-
C.
P = VI sin(φ)
-
D.
P = V²/R
Solution
The average power P in an AC circuit is given by P = VI cos(φ), where φ is the phase angle.
Correct Answer: B — P = VI cos(φ)
Learn More →
Q. What is the formula for the resonant frequency of an RLC circuit? (2021)
-
A.
f = 1/(2π√(LC))
-
B.
f = R/(2πL)
-
C.
f = 1/(2πRC)
-
D.
f = 2π√(LC)
Solution
The resonant frequency f of an RLC circuit is given by f = 1/(2π√(LC)).
Correct Answer: A — f = 1/(2π√(LC))
Learn More →
Q. What is the impedance of a circuit with a resistance of 4 ohms and a reactance of 3 ohms? (2021)
-
A.
5 ohms
-
B.
7 ohms
-
C.
1 ohm
-
D.
12 ohms
Solution
Impedance Z = √(R² + X²) = √(4² + 3²) = √(16 + 9) = √25 = 5 ohms.
Correct Answer: A — 5 ohms
Learn More →
Showing 31 to 60 of 76 (3 Pages)
