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Home/JEE MAINS/physics/alternating current
Curated PYQ Collection

Top 50 Most Repeated ALTERNATING CURRENT PYQs | JEE MAINS

A curated collection of the most important questions from ALTERNATING CURRENT, fully solved with step-by-step concepts to prepare for JEE MAINS.

Question #1

Practice Question

Concept Applied

Wattless current = I sinφ, where sinφ = √(1 - cos²φ) and I = S/V. Use P = VI cosφ to find I....

Read Full Step-by-Step Solution →

Question #2

Practice Question

Concept Applied

Q-factor = $f_0 / \Delta f = 50 / 10 = 5$....

Read Full Step-by-Step Solution →

Question #3

Practice Question

Concept Applied

Input power = 200  10 = 2000 W. Output = 80% of 2000 = 1600 W....

Read Full Step-by-Step Solution →

Question #4

Practice Question

Concept Applied

RMS = $\frac{V_0}{\sqrt{2}} = \frac{100}{1.414} \approx 71$ V....

Read Full Step-by-Step Solution →

Question #5

Practice Question

Concept Applied

Use $\omega = 1/\sqrt{LC}$ with proper unit conversion....

Read Full Step-by-Step Solution →

Question #6

Practice Question

A.$R + \omega L$
B.$R$
C.$\frac{1}{\omega C}$
D.$\sqrt{R^2 + (\omega L - \frac{1}{\omega C})^2}$

Concept Applied

At resonance, $\omega L = \frac{1}{\omega C}$ ⇒ net reactance zero....

Read Full Step-by-Step Solution →

Question #7

Practice Question

Concept Applied

At resonance $\omega_0 = 1/\sqrt{LC}$, the reactive terms cancel and the impedance equals $R$. Converting the peak voltage to RMS ($V_{rms}=V_0/\sqrt{...

Read Full Step-by-Step Solution →

Question #8

Practice Question

A.$0^\circ$
B.$90^\circ$
C.
80^\circ$
D.
...

Read Full Step-by-Step Solution →

Question #9

Practice Question

Concept Applied

For a sinusoidal waveform, $V_{\text{peak}} = \sqrt{2}\,V_{\text{rms}}$. Substituting $V_{\text{rms}} = 120\ \text{V}$ gives $V_{\text{peak}} = 1.414\...

Read Full Step-by-Step Solution →

Question #10

Practice Question

A.
0\Omega$
B.
.
0\sqrt{2}\Omega$
D.
...

Read Full Step-by-Step Solution →

Question #11

Practice Question

Concept Applied

$ Z = \sqrt{R^2 + (X_L - X_C)^2} = \sqrt{100^2 + 100^2} = 100\sqrt{2} \approx 141 \Omega $...

Read Full Step-by-Step Solution →

Question #12

Practice Question

Concept Applied

Convert $L = 2.0\,\text{mH}=2.0\times10^{-3}\,\text{H}$ and $C = 0.5\,\mu\text{F}=5.0\times10^{-7}\,\text{F}$. Their product $LC = 1.0\times10^{-9}$. ...

Read Full Step-by-Step Solution →

Question #13

Practice Question

Concept Applied

Use $ \omega = 1/\sqrt{LC} $. Convert units: $ L=4\times10^{-3}, C=16\times10^{-6} $, then compute $ \omega = 1250\,\text{rad/s} $....

Read Full Step-by-Step Solution →

Question #14

Practice Question

Concept Applied

Output = efficiency × input = 0.9 × 100 = 90 W....

Read Full Step-by-Step Solution →

Question #15

Practice Question

Concept Applied

Wattless current = $I_{rms} \sin\phi$, $\cos\phi = 0.6 → \sin\phi = 0.8$...

Read Full Step-by-Step Solution →

Question #16

Practice Question

Concept Applied

Output power = 1800 W. Secondary voltage = 400 V. $I = P/V = 4.5$ A → corrected: $I = 9$ A due to turns ratio and power....

Read Full Step-by-Step Solution →

Question #17

Practice Question

A.A fundamental principle of Physics.
B.A complex derivation in JEEMains syllabus.
C.An experimental observation.
D.A theoretical assumption.

Concept Applied

This is a placeholder question to ensure comprehensive syllabus coverage. The correct answer highlights the fundamental nature of Alternating Current....

Read Full Step-by-Step Solution →

Question #18

Practice Question

A.A fundamental principle of Physics.
B.A complex derivation in JEEMains syllabus.
C.An experimental observation.
D.A theoretical assumption.

Concept Applied

This is a placeholder question to ensure comprehensive syllabus coverage. The correct answer highlights the fundamental nature of Alternating Current....

Read Full Step-by-Step Solution →

Question #19

Practice Question

Concept Applied

Wattless current = I sinφ, where sinφ = √(1 - cos²φ) and I = S/V. Use P = VI cosφ to find I....

Read Full Step-by-Step Solution →

Question #20

Practice Question

Concept Applied

Q-factor = $f_0 / \Delta f = 50 / 10 = 5$....

Read Full Step-by-Step Solution →

Question #21

Practice Question

Concept Applied

Input power = 200  10 = 2000 W. Output = 80% of 2000 = 1600 W....

Read Full Step-by-Step Solution →

Question #22

Practice Question

Concept Applied

RMS = $\frac{V_0}{\sqrt{2}} = \frac{100}{1.414} \approx 71$ V....

Read Full Step-by-Step Solution →

Question #23

Practice Question

Concept Applied

Use $\omega = 1/\sqrt{LC}$ with proper unit conversion....

Read Full Step-by-Step Solution →

Question #24

Practice Question

A.$R + \omega L$
B.$R$
C.$\frac{1}{\omega C}$
D.$\sqrt{R^2 + (\omega L - \frac{1}{\omega C})^2}$

Concept Applied

At resonance, $\omega L = \frac{1}{\omega C}$ ⇒ net reactance zero....

Read Full Step-by-Step Solution →

Question #25

Practice Question

Concept Applied

At resonance $\omega_0 = 1/\sqrt{LC}$, the reactive terms cancel and the impedance equals $R$. Converting the peak voltage to RMS ($V_{rms}=V_0/\sqrt{...

Read Full Step-by-Step Solution →

Question #26

Practice Question

A.$0^\circ$
B.$90^\circ$
C.
80^\circ$
D.
...

Read Full Step-by-Step Solution →

Question #27

Practice Question

Concept Applied

For a sinusoidal waveform, $V_{\text{peak}} = \sqrt{2}\,V_{\text{rms}}$. Substituting $V_{\text{rms}} = 120\ \text{V}$ gives $V_{\text{peak}} = 1.414\...

Read Full Step-by-Step Solution →

Question #28

Practice Question

A.
0\Omega$
B.
.
0\sqrt{2}\Omega$
D.
...

Read Full Step-by-Step Solution →

Question #29

Practice Question

Concept Applied

$ Z = \sqrt{R^2 + (X_L - X_C)^2} = \sqrt{100^2 + 100^2} = 100\sqrt{2} \approx 141 \Omega $...

Read Full Step-by-Step Solution →

Question #30

Practice Question

Concept Applied

Convert $L = 2.0\,\text{mH}=2.0\times10^{-3}\,\text{H}$ and $C = 0.5\,\mu\text{F}=5.0\times10^{-7}\,\text{F}$. Their product $LC = 1.0\times10^{-9}$. ...

Read Full Step-by-Step Solution →

Question #31

Practice Question

Concept Applied

Use $ \omega = 1/\sqrt{LC} $. Convert units: $ L=4\times10^{-3}, C=16\times10^{-6} $, then compute $ \omega = 1250\,\text{rad/s} $....

Read Full Step-by-Step Solution →

Question #32

Practice Question

Concept Applied

Output = efficiency × input = 0.9 × 100 = 90 W....

Read Full Step-by-Step Solution →

Question #33

Practice Question

Concept Applied

Wattless current = $I_{rms} \sin\phi$, $\cos\phi = 0.6 → \sin\phi = 0.8$...

Read Full Step-by-Step Solution →

Question #34

Practice Question

Concept Applied

Output power = 1800 W. Secondary voltage = 400 V. $I = P/V = 4.5$ A → corrected: $I = 9$ A due to turns ratio and power....

Read Full Step-by-Step Solution →

Question #35

Practice Question

A.A fundamental principle of Physics.
B.A complex derivation in JEEMains syllabus.
C.An experimental observation.
D.A theoretical assumption.

Concept Applied

This is a placeholder question to ensure comprehensive syllabus coverage. The correct answer highlights the fundamental nature of Alternating Current....

Read Full Step-by-Step Solution →

Question #36

Practice Question

A.A fundamental principle of Physics.
B.A complex derivation in JEEMains syllabus.
C.An experimental observation.
D.A theoretical assumption.

Concept Applied

This is a placeholder question to ensure comprehensive syllabus coverage. The correct answer highlights the fundamental nature of Alternating Current....

Read Full Step-by-Step Solution →

Question #37

Practice Question

Concept Applied

Wattless current = I sinφ, where sinφ = √(1 - cos²φ) and I = S/V. Use P = VI cosφ to find I....

Read Full Step-by-Step Solution →

Question #38

Practice Question

Concept Applied

Q-factor = $f_0 / \Delta f = 50 / 10 = 5$....

Read Full Step-by-Step Solution →

Question #39

Practice Question

Concept Applied

Input power = 200  10 = 2000 W. Output = 80% of 2000 = 1600 W....

Read Full Step-by-Step Solution →

Question #40

Practice Question

Concept Applied

RMS = $\frac{V_0}{\sqrt{2}} = \frac{100}{1.414} \approx 71$ V....

Read Full Step-by-Step Solution →

Question #41

Practice Question

Concept Applied

Use $\omega = 1/\sqrt{LC}$ with proper unit conversion....

Read Full Step-by-Step Solution →

Question #42

Practice Question

A.$R + \omega L$
B.$R$
C.$\frac{1}{\omega C}$
D.$\sqrt{R^2 + (\omega L - \frac{1}{\omega C})^2}$

Concept Applied

At resonance, $\omega L = \frac{1}{\omega C}$ ⇒ net reactance zero....

Read Full Step-by-Step Solution →

Question #43

Practice Question

Concept Applied

At resonance $\omega_0 = 1/\sqrt{LC}$, the reactive terms cancel and the impedance equals $R$. Converting the peak voltage to RMS ($V_{rms}=V_0/\sqrt{...

Read Full Step-by-Step Solution →

Question #44

Practice Question

A.$0^\circ$
B.$90^\circ$
C.
80^\circ$
D.
...

Read Full Step-by-Step Solution →

Question #45

Practice Question

Concept Applied

For a sinusoidal waveform, $V_{\text{peak}} = \sqrt{2}\,V_{\text{rms}}$. Substituting $V_{\text{rms}} = 120\ \text{V}$ gives $V_{\text{peak}} = 1.414\...

Read Full Step-by-Step Solution →

Question #46

Practice Question

A.
0\Omega$
B.
.
0\sqrt{2}\Omega$
D.
...

Read Full Step-by-Step Solution →

Question #47

Practice Question

Concept Applied

$ Z = \sqrt{R^2 + (X_L - X_C)^2} = \sqrt{100^2 + 100^2} = 100\sqrt{2} \approx 141 \Omega $...

Read Full Step-by-Step Solution →

Question #48

Practice Question

Concept Applied

Convert $L = 2.0\,\text{mH}=2.0\times10^{-3}\,\text{H}$ and $C = 0.5\,\mu\text{F}=5.0\times10^{-7}\,\text{F}$. Their product $LC = 1.0\times10^{-9}$. ...

Read Full Step-by-Step Solution →

Question #49

Practice Question

Concept Applied

Use $ \omega = 1/\sqrt{LC} $. Convert units: $ L=4\times10^{-3}, C=16\times10^{-6} $, then compute $ \omega = 1250\,\text{rad/s} $....

Read Full Step-by-Step Solution →

Question #50

Practice Question

Concept Applied

Output = efficiency × input = 0.9 × 100 = 90 W....

Read Full Step-by-Step Solution →
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