Alternating Current
Practice Questions
MCQ (Single Correct Answer)
1

A circuit with an electrical load having impedance $Z$ is connected with an AC source as shown in the diagram. The source voltage varies in time as $V(t)=300 \sin (400 t) \mathrm{V}$, where $t$ is time in s . List-I shows various options for the load. The possible currents $i(t)$ in the circuit as a function of time are given in List-II.

JEE Advanced 2025 Paper 1 Online Physics - Alternating Current Question 1 English 1

Choose the option that describes the correct match between the entries in List-I to those in ListII.

List–I List–II
(P) JEE Advanced 2025 Paper 1 Online Physics - Alternating Current Question 1 English 2 (1) JEE Advanced 2025 Paper 1 Online Physics - Alternating Current Question 1 English 3
(Q) JEE Advanced 2025 Paper 1 Online Physics - Alternating Current Question 1 English 4 (2) JEE Advanced 2025 Paper 1 Online Physics - Alternating Current Question 1 English 5
(R) JEE Advanced 2025 Paper 1 Online Physics - Alternating Current Question 1 English 6 (3) JEE Advanced 2025 Paper 1 Online Physics - Alternating Current Question 1 English 7
(S) JEE Advanced 2025 Paper 1 Online Physics - Alternating Current Question 1 English 8 (4) JEE Advanced 2025 Paper 1 Online Physics - Alternating Current Question 1 English 9
(5) JEE Advanced 2025 Paper 1 Online Physics - Alternating Current Question 1 English 10
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2

The circuit shown in the figure contains an inductor $L$, a capacitor $C_0$, a resistor $R_0$ and an ideal battery. The circuit also contains two keys $\mathrm{K}_1$ and $\mathrm{K}_2$. Initially, both the keys are open and there is no charge on the capacitor. At an instant, key $\mathrm{K}_1$ is closed and immediately after this the current in $R_0$ is found to be $I_1$. After a long time, the current attains a steady state value $I_2$. Thereafter, $\mathrm{K}_2$ is closed and simultaneously $\mathrm{K}_1$ is opened and the voltage across $C_0$ oscillates with amplitude $V_0$ and angular frequency $\omega_0$.

JEE Advanced 2024 Paper 1 Online Physics - Alternating Current Question 3 English

Match the quantities mentioned in List-I with their values in List-II and choose the correct option.

List-I List-II
(P) The value of $I_1$ in Ampere is (1) $0$
(Q) The value of $I_2$ in Ampere is (2) $2$
(R) The value of $\omega_0$ in kilo-radians/s is (3) $4$
(S) The value of $V_0$ in Volt is (4) $20$
(5) $200$
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3
A series LCR circuit is connected to a $45 \sin (\omega t)$ Volt source. The resonant angular frequency of the circuit is $10^5 ~\mathrm{rad}~ \mathrm{s}^{-1}$ and current amplitude at resonance is $I_0$. When the angular frequency of the source is $\omega=8 \times 10^4 ~\mathrm{rad} ~\mathrm{s}^{-1}$, the current amplitude in the circuit is $0.05 I_0$. If $L=50 ~\mathrm{mH}$, match each entry in List-I with an appropriate value from List-II and choose the correct option.

List - I List - II
(P) $I_0$ in $\mathrm{mA}$ (1) 44.4
(Q) The quality factor of the circuit (2) 18
(R) The bandwidth of the circuit in $\mathrm{rad}~ \mathrm{s}^{-1}$ (3) 400
(S) The peak power dissipated at resonance in Watt (4) 2250
(5) 500
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4

In the method using the transformers, assume that the ratio of the number of turns in the primary to that in the secondary in the step-up transformer is 1 : 10. If the power of the consumers has to be supplied at 200 V, the ratio of the number of turns in the primary to that in the secondary in the step-down transformer is

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5

You are given many resistances, capacitors and inductors. These are connected to a variable DC voltage source (the first two circuits) or an AC voltage source of 50 Hz frequency (the next three circuits) in different ways as shown in Column II. When a current I (steady state for DC or rms for AC) flows through the circuit, the corresponding voltage $V_1$ and $V_2$ (indicated in circuits) are related as shown in Column I. Match the two :

IIT-JEE 2010 Paper 2 Offline Physics - Alternating Current Question 2 English 1 IIT-JEE 2010 Paper 2 Offline Physics - Alternating Current Question 2 English 2
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6

An AC voltage source of variable angular frequency $$\omega$$ and fixed amplitude V0 is connected in series with a capacitance C and an electric bulb of resistance R (inductance zero). When $$\omega$$ is increased

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7

STATEMENT 1

A vertical iron rod has a coil of wire wound over it at the bottom end. An alternating current flows in the coil. The rod goes through a conducting ring as shown in the figure. The ring can float at a certain height above the coil.

IIT-JEE 2007 Paper 2 Offline Physics - Alternating Current Question 5 English

Because

STATEMENT 2

In the above situation, a current is induced in the ring which interacts with the horizontal component of the magnetic field to produce an average force in the upward direction.

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MCQ (More than One Correct Answer)
1
The instantaneous voltages at three terminals marked $$X,Y$$ and $$Z$$ are given by

$${V_x} = {V_0}\,\sin \,\omega t,$$

$${V_Y} = {V_0}\,\sin $$ $$\left( {\omega t + {{2\pi } \over 3}} \right)$$

and $$Vz = {V_0}\sin \left( {\omega t + {{4\pi } \over 3}} \right)$$

An ideal voltmeter is configured to read $$rms$$ value of the potential difference between its terminals. It is connected between points $$X$$ and $$Y$$ and then between $$Y$$ and $$Z.$$ The reading(s) of the voltmeter will be
JEE Advanced 2017 Paper 2 Offline
2
In the circuit shown, $$L = 1\,\mu H,C = 1\,\mu F\,$$ and $$R = 1\,k\Omega .$$ They are connected in series with an a.c. source $$V = {V_0}\sin \omega t$$ as shown.

Which of the following options is/are correct?

JEE Advanced 2017 Paper 1 Offline Physics - Alternating Current Question 15 English
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3
At time t = 0, terminal A in the circuit shown in the figure is connected to B by a key and an alternating current I(t) = I0 cos ($$\omega$$t), with I0 = 1 A and $$\omega$$ = 500 rad s-1 starts flowing in it with the initial direction shown in the figure. At $$t = {{7\pi } \over {6\omega }}$$, the key is switched from B to D. Now onwards only A and D are connected. A total charge Q flows from the battery to charge the capacitor fully. If C = 20 $$\mu$$F, R = 10 $$\Omega$$ and the battery is ideal with emf of 50 V, identify the correct statement(s).

JEE Advanced 2014 Paper 1 Offline Physics - Alternating Current Question 11 English
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4

In the given circuit, the AC source has $$\omega$$ = 100 rad/s. Considering the inductor and capacitor to be ideal, the correct choice(s) is(are)

IIT-JEE 2012 Paper 2 Offline Physics - Alternating Current Question 9 English

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5

A series RC-current is connected to AC voltage source. Consider two cases : (A) When C is without a dielectric medium and (B) when C is filled with dielectric of constant 4. The current IR through the resistor and voltage VC across the capacitor are compared in the two cases. Which of the following is/are true?

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