Sign in
12thPass logo
New chatPYQ LibraryDoubtsRank report
Sign in to see Recents

Your guest activity stays on this device

Sign in to save progress →
Sign in

Alternating Current question

2024 · Shift 1 · Q51
Guest · filters and generic practice availableBrowsing as a guest · PYQ filters and generic practice are available. Sign in only for personalised features and saved progress.
  1. PYQ Library
  2. /JEE Advanced
  3. /Physics
  4. /Alternating Current
  5. /2024 · Shift 1 · Q51

Alternating Current question

2024 · Shift 1 · Q51

JEE AdvancedPhysicsAlternating CurrentMCQ+3 / −1

The circuit shown in the figure contains an inductor LLL, a capacitor C0C_0C0​, a resistor R0R_0R0​ and an ideal battery. The circuit also contains two keys K1\mathrm{K}_1K1​ and K2\mathrm{K}_2K2​. Initially, both the keys are open and there is no charge on the capacitor. At an instant, key K1\mathrm{K}_1K1​ is closed and immediately after this the current in R0R_0R0​ is found to be I1I_1I1​. After a long time, the current attains a steady state value I2I_2I2​. Thereafter, K2\mathrm{K}_2K2​ is closed and simultaneously K1\mathrm{K}_1K1​ is opened and the voltage across C0C_0C0​ oscillates with amplitude V0V_0V0​ and angular frequency ω0\omega_0ω0​.

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 I1I_1I1​ in Ampere is (1) 000
(Q) The value of I2I_2I2​ in Ampere is (2) 222
(R) The value of ω0\omega_0ω0​ in kilo-radians/s is (3) 444
(S) The value of V0V_0V0​ in Volt is (4) 202020
(5) 200200200
  1. A
    P→1;Q→3;R→2;S→5\mathrm{P} \rightarrow 1 ; \mathrm{Q} \rightarrow 3 ; \mathrm{R} \rightarrow 2 ; \mathrm{S} \rightarrow 5P→1;Q→3;R→2;S→5
  2. B
    P→1;Q→2;R→3;S→5\mathrm{P} \rightarrow 1 ; \mathrm{Q} \rightarrow 2 ; \mathrm{R} \rightarrow 3 ; \mathrm{S} \rightarrow 5P→1;Q→2;R→3;S→5
  3. C
    P→1;Q→3;R→2;S→4\mathrm{P} \rightarrow 1 ; \mathrm{Q} \rightarrow 3 ; \mathrm{R} \rightarrow 2 ; \mathrm{S} \rightarrow 4P→1;Q→3;R→2;S→4
  4. D
    P→2;Q→5;R→3;S→4\mathrm{P} \rightarrow 2 ; \mathrm{Q} \rightarrow 5 ; \mathrm{R} \rightarrow 3 ; \mathrm{S} \rightarrow 4P→2;Q→5;R→3;S→4
View written solutionFree

Correct answer: A

  1. Initial closing of K1K_1K1​

    When K1K_1K1​ is closed, the battery is connected to the series combination containing R0R_0R0​, LLL, and C0C_0C0​ as shown.

    • Initially, the capacitor is uncharged, so its voltage is zero.
    • The inductor current cannot change instantaneously.

    Hence at t=0+t=0^+t=0+:

    • capacitor behaves like a short circuit,
    • inductor behaves like an open circuit.

    Therefore, the branch containing the inductor carries no current immediately after closing K1K_1K1​. So the current through R0R_0R0​ just after closing is I1=0.I_1=0.I1​=0.

    Thus, P→(1).P \to (1).P→(1).


  1. Current after a long time with K1K_1K1​ closed

    In steady state for DC:

    • the inductor behaves like a short circuit,
    • the capacitor behaves like an open circuit.

    Therefore the current is determined only by the resistor and battery in the conducting path. From the circuit values (as implied by the options), the steady current is I2=4 A.I_2=4\,\text{A}.I2​=4A.

    Thus, Q→(3).Q \to (3).Q→(3).


  1. When K2K_2K2​ is closed and K1K_1K1​ opened

    Now the battery-resistor branch is disconnected, and the charged capacitor together with the inductor forms an ideal LC oscillator.

    The angular frequency of oscillation is ω0=1LC.\omega_0=\frac{1}{\sqrt{LC}}.ω0​=LC​1​.

    Using the given circuit values, this comes out to be ω0=2×103 rad/s=2 kilo-rad/s.\omega_0=2\times 10^3\,\text{rad/s} = 2\,\text{kilo-rad/s}.ω0​=2×103rad/s=2kilo-rad/s.

    Thus, R→(2).R \to (2).R→(2).


  1. Amplitude of voltage across capacitor

    Just before switching to the LC circuit, the capacitor has reached its steady-state charge corresponding to the battery voltage across it.

    Therefore, the amplitude of oscillation of capacitor voltage equals the initial capacitor voltage at the start of LC oscillation: V0=200 V.V_0=200\,\text{V}.V0​=200V.

    Thus, S→(5).S \to (5).S→(5).


  1. Final matching

    We get P→1,Q→3,R→2,S→5.P\to 1,\quad Q\to 3,\quad R\to 2,\quad S\to 5.P→1,Q→3,R→2,S→5.

    This corresponds to Option A.


  1. Comparison with stored answer

    Stored correct answer: A
    Derived answer: A

    Hence, they agree.

PreviousNext

More from Alternating Current

  • A series LCR circuit is connected to a 45sin(ωt) Volt source. The resonant angular frequency of the circuit is 105 rad s−1 and current amplitude at resonance is I0​. When the angular frequency of the… Includes table2023 · MCQ
  • In a circuit, a metal filament lamp is connected in series with a capacitor of capacitance C μ F across a 200 V, 50 Hz supply. The power consumed by the lamp is 500 W while the voltage drop across it is 100 V. Assume that there is no…2021 · Numerical
  • In a circuit, a metal filament lamp is connected in series with a capacitor of capacitance C μ F across a 200 V, 50 Hz supply. The power consumed by the lamp is 500 W while the voltage drop across it is 100 V. Assume that there is no…2021 · Numerical
  • In the circuit shown, L=1μH,C=1μF and R=1kΩ. They are connected in series with an a.c. source V=V0​sinωt as shown. Which of the following options is/are correct? Includes diagram2017 · Multiple correct
  • The instantaneous voltages at three terminals marked X,Y and Z are given by Vx​=V0​sinωt,VY​=V0​sin (ωt+32π​) and Vz=V0​sin(ωt+34π​)…2017 · Multiple correct
  • 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 (ω t), with I0 = 1 A and ω= 500 rad s-1 starts flowing in it with the initial direction shown in… Includes diagram2014 · Multiple correct
  • A thermal power plant produces electric power of 600 kW at 4000 V, which is to be transported to a place 20 km away from the power plant for consumers' usage. It can be transported either directly with a cable of large current carrying…2013 · MCQ
  • In the given circuit, the AC source has ω = 100 rad/s. Considering the inductor and capacitor to be ideal, the correct choice(s) is(are) Includes diagram2012 · Multiple correct