Q. If the voltage across an inductor is 12V and the current is 2A, what is the inductive reactance? (2023)
A.
6Ω
B.
12Ω
C.
24Ω
D.
18Ω
Show solution
Solution
Inductive reactance XL = V/I = 12V/2A = 6Ω.
Correct Answer:
A
— 6Ω
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Q. In a parallel RLC circuit, if R = 50 ohms, L = 0.2H, and C = 50μF, what is the total admittance? (2023)
A.
0.02 S
B.
0.04 S
C.
0.06 S
D.
0.08 S
Show solution
Solution
Y = 1/R + j(ωC - 1/ωL); calculate Y for given values.
Correct Answer:
C
— 0.06 S
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Q. In a parallel RLC circuit, if R = 50Ω, L = 0.2 H, and C = 50μF, what is the quality factor Q? (2015)
Show solution
Solution
Quality factor Q = (1/R) * √(L/C) = (1/50) * √(0.2/50e-6) = 2.
Correct Answer:
B
— 2
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Q. In a parallel RLC circuit, if the resistance is 10Ω, inductance is 0.2H, and capacitance is 50μF, what is the total current at resonance? (2022)
A.
0.5A
B.
1A
C.
2A
D.
4A
Show solution
Solution
At resonance, total current I = V/R. Calculate using V = 10V.
Correct Answer:
B
— 1A
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Q. In a parallel RLC circuit, if the resistance is 10Ω, inductance is 0.2H, and capacitance is 50μF, what is the total admittance? (2022)
A.
0.1 S
B.
0.2 S
C.
0.3 S
D.
0.4 S
Show solution
Solution
Total admittance Y = 1/R + j(ωC - 1/ωL). Calculate Y using given values.
Correct Answer:
C
— 0.3 S
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Q. In a parallel RLC circuit, if the resistance is 10Ω, inductance is 0.2H, and capacitance is 50μF, what is the quality factor Q? (2021)
Show solution
Solution
Quality factor Q = (1/R) * √(L/C) = (1/10) * √(0.2/50e-6) ≈ 3.
Correct Answer:
C
— 3
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Q. In a purely capacitive AC circuit, the current leads the voltage by how many degrees? (2022)
A.
0°
B.
90°
C.
180°
D.
270°
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Solution
In a purely capacitive circuit, the current leads the voltage by 90°.
Correct Answer:
B
— 90°
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Q. In a purely capacitive AC circuit, the current leads the voltage by how much phase angle? (2023)
A.
0 degrees
B.
90 degrees
C.
180 degrees
D.
270 degrees
Show solution
Solution
In a purely capacitive circuit, the current leads the voltage by 90 degrees.
Correct Answer:
B
— 90 degrees
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Q. In a series RLC circuit, if R = 10 ohms, L = 0.1H, and C = 100μF, what is the resonant frequency? (2021)
A.
159.15 Hz
B.
100 Hz
C.
50 Hz
D.
200 Hz
Show solution
Solution
f0 = 1 / (2π√(LC)) = 1 / (2π√(0.1 × 100 × 10^-6)) = 159.15 Hz.
Correct Answer:
A
— 159.15 Hz
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Q. In a series RLC circuit, if R = 20Ω, L = 0.1 H, and C = 100μF, what is the resonant frequency? (2020)
A.
50 Hz
B.
100 Hz
C.
159.15 Hz
D.
200 Hz
Show solution
Solution
Resonant frequency f₀ = 1 / (2π√(LC)) = 1 / (2π√(0.1 * 100e-6)) = 159.15 Hz.
Correct Answer:
C
— 159.15 Hz
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Q. In a series RLC circuit, if the inductive reactance is greater than the capacitive reactance, what type of circuit is it? (2022)
A.
Resonant
B.
Inductive
C.
Capacitive
D.
Purely resistive
Show solution
Solution
If inductive reactance (XL) is greater than capacitive reactance (XC), the circuit is inductive.
Correct Answer:
B
— Inductive
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Q. In a series RLC circuit, if the inductive reactance is greater than the capacitive reactance, the circuit is said to be: (2019)
A.
Resonant
B.
Capacitive
C.
Inductive
D.
Purely resistive
Show solution
Solution
If inductive reactance (XL) is greater than capacitive reactance (XC), the circuit is inductive.
Correct Answer:
C
— Inductive
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Q. In a series RLC circuit, if the resistance is 10 ohms, inductance is 0.1 H, and capacitance is 100 μF, what is the resonant frequency? (2021)
A.
50 Hz
B.
100 Hz
C.
159 Hz
D.
200 Hz
Show solution
Solution
Resonant frequency f = 1/(2π√(LC)) = 1/(2π√(0.1 * 100e-6)) = 159.15 Hz.
Correct Answer:
C
— 159 Hz
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Q. In a series RLC circuit, if the resistance is 10Ω, inductance is 0.1H, and capacitance is 100μF, what is the resonant frequency? (2021)
A.
50Hz
B.
100Hz
C.
159Hz
D.
200Hz
Show solution
Solution
Resonant frequency f0 = 1/(2π√(LC)) = 1/(2π√(0.1*100e-6)) ≈ 159Hz.
Correct Answer:
C
— 159Hz
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Q. In a series RLC circuit, if the resistance is 4 ohms, inductance is 0.1 H, and capacitance is 100 μF, what is the resonant frequency? (2023)
A.
50 Hz
B.
100 Hz
C.
159.15 Hz
D.
200 Hz
Show solution
Solution
Resonant frequency f = 1/(2π√(LC)) = 1/(2π√(0.1 * 100e-6)) = 159.15 Hz.
Correct Answer:
C
— 159.15 Hz
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Q. In a series RLC circuit, if the resistance is 5Ω, inductance is 0.1H, and capacitance is 100μF, what is the resonant frequency? (2022)
A.
50Hz
B.
100Hz
C.
159Hz
D.
200Hz
Show solution
Solution
The resonant frequency f = 1/(2π√(LC)) = 1/(2π√(0.1*100e-6)) ≈ 159Hz.
Correct Answer:
C
— 159Hz
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Q. In a series RLC circuit, if the resistance is 5Ω, the inductance is 0.2H, and the capacitance is 10μF, what is the resonant frequency? (2023)
A.
50Hz
B.
100Hz
C.
159.15Hz
D.
200Hz
Show solution
Solution
Resonant frequency f0 = 1/(2π√(LC)) = 1/(2π√(0.2 * 10e-6)) = 159.15Hz.
Correct Answer:
C
— 159.15Hz
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Q. In a series RLC circuit, if the total impedance is 40 Ω, the resistance is 30 Ω, what is the inductive reactance? (2021)
A.
10 Ω
B.
20 Ω
C.
30 Ω
D.
50 Ω
Show solution
Solution
Using Z = √(R² + Xl²), we have 40 = √(30² + Xl²). Solving gives Xl = 10 Ω.
Correct Answer:
A
— 10 Ω
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Q. In a series RLC circuit, if the total impedance is 50Ω, the resistance is 30Ω, what is the inductive reactance if the capacitive reactance is 20Ω? (2023)
A.
10Ω
B.
20Ω
C.
30Ω
D.
40Ω
Show solution
Solution
Using Z = √(R² + (XL - XC)²), we find XL = √(50² - 30²) + 20 = 10Ω.
Correct Answer:
A
— 10Ω
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Q. In a series RLC circuit, what condition must be met for resonance to occur? (2021)
A.
R = 0
B.
XL = XC
C.
R = XL
D.
R = XC
Show solution
Solution
For resonance in a series RLC circuit, the condition XL = XC must be met.
Correct Answer:
B
— XL = XC
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Q. In an AC circuit, if the current is given by I(t) = I0 cos(ωt), what is the RMS current? (2021)
A.
I0/√2
B.
I0
C.
2I0
D.
I0/2
Show solution
Solution
The RMS value of a cosine function is I0/√2.
Correct Answer:
A
— I0/√2
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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
Show solution
Solution
Inductive reactance (XL) = 2πfL = 2π(60)(0.2) ≈ 75.36Ω.
Correct Answer:
B
— 37.68Ω
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Q. In an AC circuit, if the frequency is increased, what happens to the capacitive reactance? (2020)
A.
It increases
B.
It decreases
C.
It remains constant
D.
It becomes zero
Show solution
Solution
Capacitive reactance XC = 1/(2πfC) decreases as frequency f increases.
Correct Answer:
B
— It decreases
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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
Show solution
Solution
Inductive reactance (XL = 2πfL) increases with an increase in frequency.
Correct Answer:
A
— It increases
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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°
Show solution
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°
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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
Show solution
Solution
The impedance Z = √(R² + XL²) = √(10² + 20²) = √(100 + 400) = √500 = 22.36 ohms.
Correct Answer:
C
— √(10² + 20²)
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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
Show solution
Solution
The total impedance Z = √(R² + XL²) = √(10² + 20²) = √(100 + 400) = √500 = 22.36 ohms.
Correct Answer:
C
— √(10² + 20²)
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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
Show solution
Solution
The total impedance Z = √(R² + XL²) = √(10² + 20²) = √(100 + 400) = √500 = 22.36Ω.
Correct Answer:
C
— √(10² + 20²)
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Q. In an AC circuit, if the total current is 5A and the total voltage is 100V, what is the impedance? (2021)
A.
20Ω
B.
25Ω
C.
30Ω
D.
15Ω
Show solution
Solution
Impedance Z = V/I = 100V/5A = 20Ω.
Correct Answer:
B
— 25Ω
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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
Show solution
Solution
Real power P = V * I * power factor = 120 * 10 * 0.8 = 960 W.
Correct Answer:
A
— 960 W
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Showing 31 to 60 of 122 (5 Pages)
AC Circuits MCQ & Objective Questions
Understanding AC Circuits is crucial for students preparing for school exams and competitive tests in India. Mastering this topic not only enhances your conceptual clarity but also boosts your confidence in tackling objective questions. Practicing AC Circuits MCQs and important questions will significantly improve your exam performance and help you score better.
What You Will Practise Here
Fundamental concepts of alternating current (AC) and its characteristics
Key formulas related to AC circuits, including impedance and reactance
Phase difference and its impact on AC circuit behavior
Resonance in AC circuits and its applications
AC circuit analysis techniques, including series and parallel circuits
Diagrams illustrating AC waveforms and circuit configurations
Real-world applications of AC circuits in electrical engineering
Exam Relevance
AC Circuits is a vital topic in various examinations, including CBSE, State Boards, NEET, and JEE. Questions related to AC Circuits often appear in both theoretical and practical formats. Students can expect to encounter problems involving calculations of current, voltage, and power in AC circuits, as well as conceptual questions that test their understanding of waveforms and circuit behavior. Familiarity with common question patterns will aid in effective exam preparation.
Common Mistakes Students Make
Confusing AC with DC concepts, leading to incorrect application of formulas
Misunderstanding phase relationships between voltage and current
Overlooking the significance of reactance in circuit analysis
Failing to accurately interpret circuit diagrams
Neglecting the practical applications of AC circuits in real-life scenarios
FAQs
Question: What are the key differences between AC and DC circuits?Answer: AC circuits involve alternating current that changes direction periodically, while DC circuits involve direct current that flows in one direction.
Question: How can I improve my understanding of AC Circuits for exams?Answer: Regular practice of AC Circuits MCQ questions and reviewing important concepts will enhance your understanding and retention.
Now is the time to take charge of your learning! Dive into our practice MCQs on AC Circuits and test your understanding. The more you practice, the better prepared you will be for your exams!
