How many questions from Alternating Currents appear in JEE?

Alternating Currents has appeared in 108 of the last 186 JEE Main and JEE Advanced papers — about 58% of them — contributing 140 questions in total across those papers.

Is Alternating Currents an important chapter for JEE?

Judged by how often it is actually tested, it appears in roughly 58% of papers. Chapters above about 50% are effectively guaranteed to show up every session, so they repay thorough preparation; lower-frequency chapters are better treated as targeted revision.

Where do these Alternating Currents questions come from?

Every question is from an official JEE Main or JEE Advanced paper, transcribed from the original paper and tagged to this chapter. Answers follow the official answer key.

Alternating Currents JEE Previous Year Questions with Answers

Q1·PhysicsSingle correctJEE Main 2026

A LCR series circuit driven with

E_{rms} = 90

V at frequency

f_d = 30

Hz has resistance

R = 80

Ω, an inductance with inductive reactance

X_L = 20.0

Ω and capacitance with capacitive reactance

X_C = 80.0

Ω. The power factor of the circuit is _______.

(A)0.8
(B)0.64
(C)0.9
(D)0.5

Q2·PhysicsSingle correctJEE Main 2026

An a.c. source of angular frequency

\omega

is connected across a resistor

R

and a capacitor

C

in series. The current is observed as

I

. Now the frequency of the source is changed to

\omega/4

, (keeping the voltage unchanged) the current is found to be

I/3

. The ratio of resistance to reactance at frequency

\omega

is

(A) $\sqrt{\frac{6}{7}}$
(B) $\sqrt{\frac{3}{5}}$
(C) $\sqrt{\frac{7}{8}}$
(D) $\sqrt{\frac{3}{4}}$

Q3·PhysicsNumericalJEE Main 2026

A series LCR circuit with

R = 20

Ω,

L = 1.6

H and

C = 40

μF is connected to a variable frequency a.c. source. The inductive reactance at resonant frequency is ________ Ω.

Q4·PhysicsNumericalJEE Main 2026

An inductor of 10 mH, capacitor of

0.1\ \mu

F and a resistor of

100\ \Omega

are connected in series across an

a.c

power supply 220 V, 70 Hz. The power factor of the given circuit is 0.5. The difference in the inductive reactance and capacitance reactance is

\sqrt{3}\alpha\ \Omega

. The value of

\alpha

is ______.

Q5·PhysicsSingle correctJEE Main 2026

The figure given below shows an

LCR

series circuit with two switches

S_1

and

S_2

. When switch

S_1

is closed keeping

S_2

open, the phase difference

(\phi)

between the current and source voltage is

30^\circ

and phase difference is

60^\circ

when

S_2

is closed keeping

S_1

open. The value of

(3L_1 - L_2)

is ________ H.

(A) $\frac{9}{2}$
(B) $\frac{2}{9}$
(C) $\frac{1}{3}$
(D) $3$

Q6·PhysicsNumericalJEE Main 2026

An inductor stores 16 J of magnetic field energy and dissipates 32 W of thermal energy due to its resistance when an a.c. current of 2 A (rms) and frequency 50 Hz flows through it. The ratio of inductive reactance to its resistance is _________. (π = 3.14)

Q7·PhysicsSingle correctJEE Main 2026

The electric current in the circuit is given as

i = i_{0}(t/T)

. The r.m.s current for the period

t = 0

to

t = T

is __________

(A) $\frac{i_{0}}{\sqrt{2}}$
(B) $i_{0}$
(C) $\frac{i_{0}}{\sqrt{6}}$
(D) $\frac{i_{0}}{\sqrt{3}}$

Q8·PhysicsSingle correctJEE Main 2026

For the series LCR circuit connected with 220 V, 50 Hz a.c source as shown in the figure, the power factor is

\dfrac{\alpha}{10}

. The value of α is_______

(A)4
(B)10
(C)6
(D)8

Q9·PhysicsNumericalJEE Main 2026

Using a variable-frequency a.c. voltage source, the maximum current measured in the given LCR circuit is 50 mA for V=5sin(100t). The values of L and R are shown in the figure. The capacitance of the capacitor (C) used is ______ μF.

Q10·PhysicsSingle correctJEE Main 2026

A capacitor C is first charged fully with potential difference of

V_0

and disconnected from the battery. The charged capacitor is connected across an inductor having inductance L. In t s 25% of the initial energy in the capacitor is transferred to the inductor. The value of t is________s.

(A) $\frac{\pi\sqrt{LC}}{3}$
(B) $\frac{\pi\sqrt{LC}}{6}$
(C) $\frac{\pi\sqrt{LC}}{2}$
(D) $\pi\sqrt{\frac{LC}{2}}$

Q11·PhysicsSingle correctJEE Advanced 2025

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(400t) 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. Choose the option that describes the correct match between the entries in List-I to those in ListII.

List-I	List-II
P.see figure	1.see figure
Q.see figure	2.see figure
R.see figure	3.see figure
S.see figure	4.see figure
	5.see figure

(A)(P) → (3), (Q) → (5), (R) → (2), (S) → (1)
(B)(P) → (1), (Q) → (5), (R) → (2), (S) → (3)
(C)(P) → (3), (Q) → (4), (R) → (2), (S) → (1)
(D)(P) → (1), (Q) → (4), (R) → (2), (S) → (5)

Q12·PhysicsIntegerJEE Main 2025

For ac circuit shown in figure, R = 100 k

\Omega

and C = 100 pF and the phase difference between

V_{in}

and

(V_B-V_A)

is

90^\circ

. The input signal frequency is

10^x

rad/sec, where

x

is ______.

Q13·PhysicsSingle correctJEE Main 2025

An ac current is represented as

i=5\sqrt{2}+10\cos\left(650\pi t+\dfrac{\pi}{6}\right)

Amp. The r.m.s value of the current is

(A)50 Amp
(B)100 Amp
(C)10 Amp
(D) $5\sqrt{2}$ Amp

Q14·PhysicsIntegerJEE Main 2025

An inductor of reactance 100

\Omega

, a capacitor of reactance 50

\Omega

, and a resistor of resistance 50

\Omega

are connected in series with an AC source of 10 V, 50 Hz. Average power dissipated by the circuit is __________ W.

Q15·PhysicsSingle correctJEE Main 2025

An alternating current is represented by the equation,

i=100\sqrt{2}\sin(100\pi t)

ampere. The RMS value of current and the frequency of the given alternating current are

(A) $100\sqrt{2}$ A, 100 Hz
(B) $\dfrac{100}{\sqrt{2}}$ A, 100 Hz
(C)100 A, 50 Hz
(D) $50\sqrt{2}$ A, 50 Hz

Q16·PhysicsSingle correctJEE Main 2025

An electric bulb rated as 100 W-220 V is connected to an ac source of rms voltage 220 V. The peak value of current through the bulb is:

(A)0.64 A
(B)0.45 A
(C)2.2 A
(D)0.32 A

Q17·PhysicsSingle correctJEE Main 2025

An alternating current is given by

I=I_A\sin\omega t+I_B\cos\omega t

. The r.m.s. current will be :-

(A) $\sqrt{I_A^2+I_B^2}$
(B) $\dfrac{\sqrt{I_A^2+I_B^2}}{2}$
(C) $\sqrt{\dfrac{I_A^2+I_B^2}{2}}$
(D) $\dfrac{|I_A+I_B|}{\sqrt2}$

Q18·PhysicsIntegerJEE Main 2025

In a series LCR circuit, a resistor of

300\ \Omega

, a capacitor of

25

nF and an inductor of

100

mH are used. For maximum current in the circuit, the angular frequency of the ac source is __________

\times10^4

radians

\mathrm{s^{-1}}

.

Q19·PhysicsSingle correctJEE Main 2025

A series LCR circuit is connected to an alternating source of emf E. The current amplitude at resonant frequency is

I_0

. If the value of resistance R becomes twice of its initial value then amplitude of current at resonance will be

(A) $I_0$
(B) $\frac{I_0}{2}$
(C) $\frac{I_0}{\sqrt{2}}$
(D) $2I_0$

Q20·PhysicsSingle correctJEE Advanced 2024

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

K_{1}

and

K_{2}

. Initially, both the keys are open and there is no charge on the capacitor. At an instant, key

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,

K_{2}

is closed and simultaneously

K_{1}

is opened and the voltage across

C_{0}

oscillates with amplitude

V_{0}

and angular frequency

\omega_{0}

. 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	3.4
S.The value of $V_{0}$ in Volt is	4.20
	5.200

(A)P $\to$ 1; Q $\to$ 3; R $\to$ 2; S $\to$ 5
(B)P $\to$ 1; Q $\to$ 2; R $\to$ 3; S $\to$ 5
(C)P $\to$ 1; Q $\to$ 3; R $\to$ 2 S $\to$ 4
(D)P $\to$ 2 Q $\to$ 5 R $\to$ 3 S $\to$ 4

Q21·PhysicsNumericalJEE Main 2024

A capacitor of reactance

4\sqrt{3}\,\Omega

and a resistor of resistance

4\,\Omega

are connected in series with an ac source of peak value

8\sqrt{2}

V. The power dissipation in the circuit is _______ W.

Q22·PhysicsSingle correctJEE Main 2024

A bulb and a capacitor are connected in series across an ac supply. A dielectric is then placed between the plates of the capacitor. The glow of the bulb:

(A)increases
(B)remains same
(C)becomes zero
(D)decreases

Q23·PhysicsNumericalJEE Main 2024

When a coil is connected across a 20 V dc supply, it draws a current of 5 A. When it is connected across 20 V, 50 Hz ac supply, it draws a current of 4 A. The self inductance of the coil is ______ mH. (Take

\pi=3

)

Q24·PhysicsSingle correctJEE Main 2024

A coil of negligible resistance is connected in series with a 90

\Omega

resistor across a 120 V, 60 Hz supply. A voltmeter reads 36 V across the resistance. Inductance of the coil is:

(A)0.76 H
(B)2.86 H
(C)0.286 H
(D)0.91 H

Q25·PhysicsSingle correctJEE Main 2024

A LCR circuit is at resonance for a capacitor

C

, inductance

L

and resistance

R

. Now the value of resistance is halved keeping all other parameters same. The current amplitude at resonance will be now:

(A)Zero
(B)double
(C)same
(D)halved

Q26·PhysicsNumericalJEE Main 2024

An alternating emf

E=110\sqrt{2}\sin 100t

volt is applied to a capacitor of 2

\mu

F, the rms value of current in the circuit is ________ mA.

Q27·PhysicsNumericalJEE Main 2024

For a given series LCR circuit it is found that maximum current is drawn when value of variable capacitance is

2.5

nF. If resistance of

200\,\Omega

and

100

mH inductor is being used in the given circuit. The frequency of ac source is ______

\times 10^{3}

Hz. (given

\pi^{2} = 10

)

Q28·PhysicsSingle correctJEE Main 2024

Given below are two statements: Statement I: In an LCR series circuit, current is maximum at resonance. Statement II: Current in a purely resistive circuit can never be less than that in a series LCR circuit when connected to the same voltage source. In the light of the above statements, choose the correct answer from the options given below:

(A)Statement I is true but Statement II is false
(B)Statement I is false but Statement II is true
(C)Both Statement I and Statement II are true
(D)Both Statement I and Statement II are false

Q29·PhysicsNumericalJEE Main 2024

When a dc voltage of 100 V is applied to an inductor, a current of 5 A flows through it. When an ac voltage of 200 V peak value is connected to the inductor, its inductive reactance is found to be

20\sqrt{3}\,\Omega

. The power dissipated in the circuit is _______ W.

Q30·PhysicsNumericalJEE Main 2024

An ac source

V = 50\sqrt{2}\sin(100t)

V is connected in a series LCR circuit with

L = 1

H,

R = 300\ \Omega

and

C = 20\ \mu\text{F}

. The rms potential difference across the capacitor is ___ V.

Q31·PhysicsSingle correctJEE Main 2024

A series LCR circuit is subjected to an AC signal of 200 V, 50 Hz. If the voltage across the inductor (

L=10

mH) is 31.4 V, then the current in this circuit is __________:

(A)68 A
(B)63 A
(C)10 A
(D)10 mA

Q32·PhysicsSingle correctJEE Main 2024

Match List-I (type of AC circuit) with List-II (the phasor diagram of current I and voltage V). Choose the correct answer from the options given below:

List-I	List-II
A.Purely capacitive circuit	I.see figure
B.Purely inductive circuit	II.see figure
C.LCR series at resonance	III.see figure
D.LCR series circuit	IV.see figure

(A)A-I, B-IV, C-III, D-II
(B)A-IV, B-I, C-III, D-II
(C)A-IV, B-I, C-II, D-III
(D)A-I, B-IV, C-II, D-III

Q33·PhysicsNumericalJEE Main 2024

A alternating current at any instant is given by

i=\left[6+\sqrt{56}\sin\left(100\pi t+\dfrac\pi3\right)\right]\,A

. The rms value of the current is ___ A.

Q34·PhysicsSingle correctJEE Main 2024

In an a.c. circuit, the instantaneous current is zero, when the instantaneous voltage is maximum. In this case, the source may be connected to: A. pure inductor. B. pure capacitor. C. pure resistor. D. combination of an inductor and capacitor. Choose the correct answer from the options given below:

(A)A, B and C only
(B)B, C and D only
(C)A and B only
(D)A, B and D only

Q35·PhysicsSingle correctJEE Main 2024

In series LCR circuit, the capacitance is changed from

C

to

4C

. To keep the resonance frequency unchanged, the new inductance should be:

(A)reduced by $\dfrac14 L$
(B)increased by $2L$
(C)reduced by $\dfrac34 L$
(D)increased to $4L$

Q36·PhysicsSingle correctJEE Main 2024

A transformer has an efficiency of

80\%

and works at 10 V and 4 kW. If the secondary voltage is 240 V, then the current in the secondary coil is:

(A)1.59 A
(B)13.33 A
(C)1.33 A
(D)15.1 A

Q37·PhysicsSingle correctJEE Main 2024

An AC voltage

V=20\sin 200\pi t

is applied to a series LCR circuit which drives a current

I=10\sin\left(200\pi t+\dfrac{\pi}{3}\right)

. The average power dissipated is:

(A)21.6 W
(B)200 W
(C)173.2 W
(D)50 W

Q38·PhysicsSingle correctJEE Main 2024

A series

L,R

circuit connected with an ac source

E=(25\sin1000t)\,V

has a power factor of

\dfrac{1}{\sqrt2}

. If the source of emf is changed to

E=(20\sin2000t)\,V

, the new power factor of the circuit will be:

(A) $\dfrac{1}{\sqrt2}$
(B) $\dfrac{1}{\sqrt3}$
(C) $\dfrac{1}{\sqrt5}$
(D) $\dfrac{1}{\sqrt7}$

Q39·PhysicsSingle correctJEE Main 2024

An alternating voltage

V(t)=220\sin 100\pi t

volt is applied to a purely resistive load of

50\,\Omega

. The time taken for the current to rise from half of the peak value to the peak value is:

(A)5 ms
(B)3.3 ms
(C)7.2 ms
(D)2.2 ms

Q40·PhysicsNumericalJEE Main 2024

A power transmission line feeds input power at 2.3 kV to a step down transformer with its primary winding 3000 turns. The output power is delivered at 230 V to the primary of the transformer is 5A and its efficiency is 90%. The winding of transformer is made of copper. The output current of transformer is ______ A.

Q41·PhysicsSingle correctJEE Main 2024

Primary coil of a transformer is connected to

220\,V

ac. Primary and secondary turns of the transformer are

100

and

10

respectively. Secondary coil is connected to two series resistance shown in figure. The output voltage

(V_0)

is:

(A) $7\,V$
(B) $15\,V$
(C) $44\,V$
(D) $2\,V$

Q42·PhysicsSingle correctJEE Main 2024

Primary side of a transformer is connected to 230 V, 50 Hz supply. Turns ratio of primary to secondary winding is

10:1

. Load resistance connected to secondary side is 46

\Omega

. The power consumed in it is :

(A)12.5 W
(B)10.0 W
(C)11.5 W
(D)12.0 W

Q43·PhysicsNumericalJEE Main 2024

A series LCR circuit with

L=\dfrac{100}{\pi}

mH,

C=\dfrac{10^{-3}}{\pi}

F and

R=10\,\Omega

, is connected across an ac source of 220 V, 50 Hz supply. The power factor of the circuit would be ________.

Q44·PhysicsSingle correctJEE Advanced 2023

A series LCR circuit is connected to a 45

\sin(\omega t)

Volt source. The resonant angular frequency of the circuit is

10^5

rad

s^{-1}

and current amplitude at resonance is

I_0

. When the angular frequency of the source is

\omega = 8 \times 10^4

rad

s^{-1}

, the current amplitude in the circuit is

0.05\ I_0

. If L = 50 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 mA	1.44.4
Q.The quality factor of the circuit	2.18
R.The bandwidth of the circuit in rad $s^{-1}$	3.400
S.The peak power dissipated at resonance in Watt.	4.2250
	5.500

(A)P $\rightarrow$ 2, Q $\rightarrow$ 3, R $\rightarrow$ 5, S $\rightarrow$ 1
(B)P $\rightarrow$ 3, Q $\rightarrow$ 1, R $\rightarrow$ 4, S $\rightarrow$ 2
(C)P $\rightarrow$ 4, Q $\rightarrow$ 5, R $\rightarrow$ 3, S $\rightarrow$ 1
(D)P $\rightarrow$ 4, Q $\rightarrow$ 2, R $\rightarrow$ 1, S $\rightarrow$ 5

Q45·PhysicsSingle correctJEE Main 2023

Given below are two statements: Statement I: An AC circuit undergoes electrical resonance if it contains either a capacitor or an inductor. Statement II: An AC circuit containing a pure capacitor or a pure inductor consumes high power due to its non-zero power factor. In the light of above statements, choose the correct answer from the options given below

(A)Both Statement I and Statement II are false
(B)Statement I is true but Statement II is false
(C)Both Statement I and Statement II are true
(D)Statement I is false but Statement II is true

Q46·PhysicsSingle correctJEE Main 2023

Given below are two statements: Statement I: When the frequency of an a.c. source in a series LCR circuit increases, the current in the circuit first increases, attains a maximum value and then decreases. Statement II: In a series LCR circuit, the value of power factor at resonance is one. In the light of given statements, choose the most appropriate answer from the options given below:

(A)Statement I is false but Statement II is true.
(B)Both Statement I and Statement II are false.
(C)Statement I is correct but Statement II is false.
(D)Both Statement I and Statement II are true.

Q47·PhysicsSingle correctJEE Main 2023

As per the given graph choose the correct representation for curve A and curve B. {Where

X_C

= reactance of pure capacitive circuit connected with A.C. source,

X_L

= reactance of pure inductive circuit connected with A.C. source,

R

= impedance of pure resistive circuit connected with A.C. source,

Z

= Impedance of the LCR series circuit}

(A) $A = X_C, B = R$
(B) $A = X_L, B = Z$
(C) $A = X_C, B = X_L$
(D) $A = X_L, B = R$

Q48·PhysicsSingle correctJEE Main 2023

Given below are two statements: Statement I: Maximum power is dissipated in a circuit containing an inductor, a capacitor and a resistor connected in series with an AC source, when resonance occurs. Statement II: Maximum power is dissipated in a circuit containing pure resistor due to zero phase difference between current and voltage. In the light of the above statements, choose the correct answer from the options given below:

(A)Statement I is false but Statement II is true
(B)Statement I is true but Statement II is false
(C)Both Statement I and Statement II are true
(D)Both Statement I and Statement II are false

Q49·PhysicsNumericalJEE Main 2023

An oscillating LC circuit consists of a

75\,\text{mH}

inductor and a

1.2\,\mu\text{F}

capacitor. If the maximum charge to the capacitor is

2.7\,\mu\text{C}

. The maximum current in the circuit will be ______

\text{mA}

.

Q50·PhysicsNumericalJEE Main 2023

A series combination of a resistor of resistance 100

\Omega

, an inductor of inductance 1 H and a capacitor of capacitance 6.25

\mu

F is connected to an ac source. The quality factor of the circuit will be ____.

Q51·PhysicsNumericalJEE Main 2023

An ideal transformer with purely resistive load operates at

12\,kV

on the primary side. It supplies electrical energy to a number of nearby houses at

120\,V

. The average rate of energy consumption in the houses served by the transformer is

60\,kW

. The value of resistive load

(R_s)

required in the secondary circuit will be _____

m\Omega

.

Q52·PhysicsSingle correctJEE Main 2023

A capacitor of capacitance 150.0

\mu F

is connected to an alternating source of emf given by

E = 36\sin(120\pi t)

V. The maximum value of current in the circuit is approximately equal to:

(A) $2\,A$
(B) $\frac{1}{\sqrt{2}}\,A$
(C) $\sqrt{2}\,A$
(D) $2\sqrt{2}\,A$

Q53·PhysicsNumericalJEE Main 2023

A series LCR circuit is connected to an ac source of

220

V,

50

Hz. The circuit contains a resistance

R=100\,\Omega

and an inductor of inductive reactance

X_L=79.6\,\Omega

. The capacitance of the capacitor needed to maximize the average rate at which energy is supplied will be _______

\mu

F.

Q54·PhysicsSingle correctJEE Main 2023

An alternating voltage source

V=260\sin(628t)

is connected across a pure inductor of

5

mH. Inductive reactance in the circuit is:

(A) $0.318\,\Omega$
(B) $6.28\,\Omega$
(C) $3.14\,\Omega$
(D) $0.5\,\Omega$

Q55·PhysicsNumericalJEE Main 2023

A series LCR circuit consists of

R=80\,\Omega

,

X_L=100\,\Omega

and

X_C=40\,\Omega

. The input voltage is

2500\cos(100\pi t)

V. The amplitude of current, in the circuit, is _________ A.

Q56·PhysicsSingle correctJEE Main 2023

If

R

,

X_L

and

X_C

represent resistance, inductive reactance and capacitive reactance. Then which of the following is dimensionless :

(A) $\frac{R}{X_L X_C}$
(B) $\frac{R}{\sqrt{X_L X_C}}$
(C) $R\frac{X_L}{X_C}$
(D) $RX_L X_C$

Q57·PhysicsNumericalJEE Main 2023

An inductor of

0.5

mH, a capacitor of

20\,\mu\text{F}

and resistance of

20\,\Omega

are connected in series with a

220

V ac source. If the current is in phase with the emf, the amplitude of current of the circuit is

\sqrt{x}

A. The value of

x

is-

Q58·PhysicsSingle correctJEE Main 2023

In a series AC circuit with inductive reactance

X_L=200\,\Omega

, capacitive reactance

X_C=100\,\Omega

and resistance

R=100\,\Omega

connected to a source of

V_{rms}=200\sqrt{2}

V, the rms value of current (

I_{rms}

) through the resistor R is:

(A) $2\sqrt{2}$ A
(B) $2$ A
(C) $20$ A
(D) $\dfrac{1}{2}$ A

Q59·PhysicsSingle correctJEE Main 2023

In a series LR circuit with

X_L=R

, power factor is

P_1

. If a capacitor of capacitance C with

X_C=X_L

is added to the circuit the power factor becomes

P_2

. The ratio of

P_1

to

P_2

will be:

(A) $1:3$
(B) $1:2$
(C) $1:\sqrt2$
(D) $1:1$

Q60·PhysicsNumericalJEE Main 2023

An inductor of inductance

2\,\mu H

is connected in series with a resistance, a variable capacitor and an AC source of frequency

7\,kHz

. The value of capacitance for which maximum current is drawn into the circuit is

\dfrac{1}{x}\,F

, where the value of

x

is _____.

\left(\text{Take }\pi=\dfrac{22}{7}\right)

Q61·PhysicsSingle correctJEE Main 2023

For the given figures, choose the correct options:

(A)At resonance, current in (b) is less than that in (a)
(B)The rms current in circuit (b) can never be larger than that in (a)
(C)The rms current in circuit (b) is always equal to that in (a)
(D)The rms current in circuit (b) can be larger than that in (a)

Q62·PhysicsNumericalJEE Main 2023

A series LCR circuit is connected to an AC source of 220 V, 50 Hz. The circuit contains a resistance

R = 80\,\Omega

, an inductor of inductive reactance

X_L = 70\,\Omega

, and a capacitor of capacitive reactance

X_C = 130\,\Omega

. The power factor of circuit is

\frac{x}{10}

. The value of

x

is:

Q63·PhysicsSingle correctJEE Main 2023

In an LC oscillator, if values of inductance and capacitance become twice and eight times, respectively, then the resonant frequency of oscillator becomes

x

times its initial resonant frequency

\omega_0

. The value of

x

is:

(A) $4$
(B) $\dfrac{1}{16}$
(C) $16$
(D) $\dfrac{1}{4}$

Q64·PhysicsNumericalJEE Main 2023

An LCR series circuit of capacitance 62.5 nF and resistance of

50\,\Omega

, is connected to an A.C. source of frequency 2.0 kHz. For maximum value of amplitude of current in the circuit, the value of inductance is _______ mH. (Take

\pi^2=10

)

Q65·PhysicsNumericalJEE Main 2023

In the circuit shown in the figure, the ratio of the quality factor and the band width is _______ S.

Q66·PhysicsNumericalJEE Advanced 2022

Consider an LC circuit, with inductance L=0.1 H and capacitance

C = 10^{-3}

F, kept on a plane. The area of the circuit is 1 m

^2

. It is placed in a constant magnetic field of strength

B_0

which is perpendicular to the plane of the circuit. At time t = 0, the magnetic field strength starts increasing linearly as

B = B_0 + \beta t

with

\beta = 0.04 Ts^{-1}

. The maximum magnitude of the current in the circuit is__________ mA .

Q67·PhysicsSingle correctJEE Main 2022

A circuit element X when connected to an a.c. supply of peak voltage 100 V gives a peak current of 5 A which is in phase with the voltage. A second element Y when connected to the same a.c. supply also gives the same value of peak current which lags behind the voltage by

\frac{\pi}{2}

. If X and Y are connected in series to the same supply, what will be the rms value of the current in ampere ?

(A) $\frac{10}{\sqrt{2}}$
(B) $\frac{5}{\sqrt{2}}$
(C) $5\sqrt{2}$
(D) $\frac{5}{2}$

Q68·PhysicsNumericalJEE Main 2022

A capacitor of capacitance 500 μF is charged completely using a dc supply of 100 V. It is now connected to an inductor of inductance 50 mH to form an LC circuit. The maximum current in LC circuit will be _______ A.

Q69·PhysicsSingle correctJEE Main 2022

An alternating emf E = 440 sin 100πt is applited to a circuit containing an inductance of

\frac{\sqrt{2}}{\pi}

H. If an a.c. ammeter is connected in the circuit, its reading will be :

(A)4.4 A
(B)1.55 A
(C)2.2 A
(D)3.11 A

Q70·PhysicsSingle correctJEE Main 2022

A transformer operating at primary voltage 8 kV and secondary voltage 160 V serves a load of 80 kW. Assuming the transformer to be ideal with purely resistive load and working on unity power factor, the loads in the primary and secondary circuit would be

(A)800 $\Omega$ and 1.06 $\Omega$
(B)10 $\Omega$ and 500 $\Omega$
(C)800 $\Omega$ and 0.32 $\Omega$
(D)1.06 $\Omega$ and 500 $\Omega$

Q71·PhysicsSingle correctJEE Main 2022

The equation of current in a purely inductive circuit is

5\sin\left(49\pi t - 30°\right)

. If the inductance is 30 mH then the equation for the voltage across the inductor, will be :

\left\{\text{Let } \pi = \frac{22}{7}\right\}

(A) $1.47\sin(49\pi t - 30°)$
(B) $1.47\sin(49\pi t + 60°)$
(C) $23.1\sin(49\pi t - 30°)$
(D) $23.1\sin(49\pi t + 60°)$

Q72·PhysicsNumericalJEE Main 2022

The frequencies at which the current amplitude in an LCR series circuit becomes

\frac{1}{\sqrt{2}}

times its maximum value, are 212 rad s

^{-1}

and 232 rad s

^{-1}

. The value of resistance in the circuit is R = 5Ω. The self inductance in the circuit is ________ mH.

Q73·PhysicsSingle correctJEE Main 2022

A series LCR circuit has L = 0.01 H, R = 10 Ω and C = 1 μF and it is connected to ac voltage of amplitude (

V_m

) 50 V. At frequency 60% lower than resonant frequency, the amplitude of current will be approximately :

(A)466 mA
(B)312 mA
(C)238 mA
(D)196 mA

Q74·PhysicsSingle correctJEE Main 2022

A direct current of 4 A and an alternating current of peak value 4 A flow through resistance of 3 Ω and 2 Ω respectively. The ratio of heat produced in the two resistances in same interval of time will be :

(A)3 : 2
(B)3 : 1
(C)3 : 4
(D)4 : 3

Q75·PhysicsNumericalJEE Main 2022

To light, a 50 W, 100 V lamp is connected, in series with a capacitor of capacitance

\frac{50}{\pi\sqrt{x}}\,\mu\mathrm{F}

, with 200 V, 50Hz AC source. The value of x will be ____ .

Q76·PhysicsSingle correctJEE Main 2022

In a series LR circuit X

_{L}

= R and power factor of the circuit is P

_{1}

. When capacitor with capacitance C such that X

_{L}

= X

_{C}

is put in series, the power factor becomes P

_{2}

. The ratio

\frac{P_{1}}{P_{2}}

is

(A) $\frac{1}{2}$
(B) $\frac{1}{\sqrt{2}}$
(C) $\frac{\sqrt{3}}{\sqrt{2}}$
(D)2 : 1

Q77·PhysicsNumericalJEE Main 2022

The effective current I in the given circuit at very high frequencies will be _____A

Q78·PhysicsSingle correctJEE Main 2022

To increase the resonant frequency in series LCR circuit,

(A)Source frequency should be increased
(B)Another resistance should be added in series with the first resistance.
(C)Another capacitor should be added in series with the first capacitor
(D)The source frequency should be decreased

Q79·PhysicsSingle correctJEE Main 2022

The rms value of conduction current in a parallel plate capacitor is 6.9

\mu

A. The capacity of this capacitor, if it is connected to 230 V ac supply with an angular frequency of 600 rad/s, will be :

(A)5 pF
(B)50 pF
(C)100 pF
(D)200 pF

Q80·PhysicsNumericalJEE Main 2022

An inductor of 0.5 mH, a capacitor of 200 μF and a resistor of 2 Ω are connected in series with a 220 V ac source. If the current is in phase with the emf, the frequency of ac source will be___

\times 10^2

Hz.

Q81·PhysicsSingle correctJEE Main 2022

For a series LCR circuit, I vs ω curve is shown : (a) To the left of

\omega_r

, the circuit is mainly capacitive. (b) To the left of

\omega_r

, the circuit is mainly inductive. (c) At

\omega_r

, impedance of the circuit is equal to the resistance of the circuit. (d) At

\omega_r

, impedance of the circuit is 0. Choose the most appropriate answer from the options given below :

(A)(a) and (d) only
(B)(b) and (d) only
(C)(a) and (c) only
(D)(b) and (c) only

Q82·PhysicsNumericalJEE Main 2022

A telegraph line of length loo km has a capacity of

0.01

μF/km and it carries an alternating current at

0.5

kilo cycle per second. If minimum impedance is required, then the value of the inductance that needs to be introduced in series is _________ mH.

\left(\text{if } \pi = \sqrt{10}\right)

Q83·PhysicsSingle correctJEE Main 2022

If L, C and R are the self inductance, capacitance and resistance respectively, which of the following does not have the dimension of time ?

(A)RC
(B) $\dfrac{L}{R}$
(C) $\sqrt{LC}$
(D) $\dfrac{L}{C}$

Q84·PhysicsSingle correctJEE Main 2022

The current flowing through an ac circuit is given by

I = 5\sin(120\pi t)\,A

How long will the current take to reach the peak value starting from zero?

(A) $\frac{1}{60}s$
(B)60s
(C) $\frac{1}{120}s$
(D) $\frac{1}{240}s$

Q85·PhysicsNumericalJEE Main 2022

A 220 V, 50 Hz AC source is connected to a 25 V, 5 W lamp and an additional resistance R in series (as shown in figure) to run the lamp at its peak brightness, then the value of R (in ohm) will be _______ .

Q86·PhysicsNumericalJEE Main 2022

A 110 V , 50 Hz, AC source is connected in the circuit (as shown in figure). The current through the resistance 55 Ω, at resonance in the circuit, will be ............... A.

Q87·PhysicsSingle correctJEE Main 2022

A sinusoidal voltage V(t) = 210 sin 3000t volt is applied to a series LCR circuit in which L = 10 mH, C = 25 μF and R = 100Ω. The phase difference (Φ) between the applied voltage and resultant current will be :

(A) $\tan^{-1}(0.17)$
(B) $\tan^{-1}(9.46)$
(C) $\tan^{-1}(0.30)$
(D) $\tan^{-1}(13.33)$

Q88·PhysicsSingle correctJEE Main 2022

If wattless current flows in the AC circuit, then the circuit is

(A)Purely Resistive circuit
(B)Purely Inductive circuit
(C)LCR series circuit
(D)RC series circuit only

Q89·PhysicsNumericalJEE Main 2022

In a series LCR circuit, the inductance, capacitance and resistance are L = 100mH, C = 100μF and R = 10Ω respectively. They are connected to an AC source of voltage 220V and frequency of 50 Hz. The approximate value of current in the circuit will be____ A.

Q90·PhysicsSingle correctJEE Main 2022

A resistance of 40

\Omega

is connected to a source of alternating current rated 220 V, 50 Hz. Find the time taken by the current to change from its maximum value to rms value :

(A)2.5 ms
(B)1.25 ms
(C)2.5 s
(D)0.25 s

Q91·PhysicsSingle correctJEE Main 2022

Given below are two statements : Statement-I : The reactance of an ac circuit is zero. It is possible that the circuit contains a capacitor and an inductor. Statement-II : In ac circuit, the average poser delivered by the source never becomes zero. In the light of the above statements, choose the correct answer from the options given below :

(A)Both Statement I and Statement II are true.
(B)Both Statement I and Statement II are false.
(C)Statement I is true but Statement II in false.
(D)Statement I is false but Statement II is true.

Q92·PhysicsNumericalJEE Main 2022

As shown in the figure an inductor of inductance 200 mH is connected to an AC source of emf 220 V and frequency 50 Hz. The instantaneous voltage of the source is 0 V when the peak value of current is

\dfrac{\sqrt{a}}{\pi}

A. The value of a is ________.

Q93·PhysicsNumericalJEE Advanced 2021

In a circuit, a metal filament lamp is connected in series with a capacitor of capacitance C µF 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 inductive load in the circuit. Take rms values of the voltages. The magnitude of the phase-angle (in degrees) between the current and the supply voltage is φ. Assume,

\pi\sqrt{3} \approx 5

. The value of

\varphi

is ____.

Q94·PhysicsNumericalJEE Advanced 2021

In a circuit, a metal filament lamp is connected in series with a capacitor of capacitance C µF 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 inductive load in the circuit. Take rms values of the voltages. The magnitude of the phase-angle (in degrees) between the current and the supply voltage is φ. Assume,

\pi\sqrt{3} \approx 5

. The value of C is ____.

Q95·PhysicsSingle correctJEE Main 2021

In an ac circuit, an inductor, a capacitor and a resistor are connected in series with

X_{L}=R=X_{C}

. Impedance of this circuit is :

(A) $2R^{2}$
(B)Zero
(C)R
(D) $R\sqrt{2}$

Q96·PhysicsNumericalJEE Main 2021

At very high frequencies, the effective impendance of the given circuit will be_______

\Omega

.

Q97·PhysicsNumericalJEE Main 2021

The alternating current is given by

i = \left\{\sqrt{42}\sin\left(\frac{2\pi}{T}t\right) + 10\right\}A

The r.m.s. value of this current is ........ A.

Q98·PhysicsNumericalJEE Main 2021

An ac circuit has an inductor and a resistor of resistance R in series, such that

X_L

= 3R. Now, a capacitor is added in series such that

X_C

= 2R. The ratio of new power factor with the old power factor of the circuit is

\sqrt{5}

: x . The value of x is _____ .

Q99·PhysicsSingle correctJEE Main 2021

A series LCR circuit driven by 300 V at a frequency of 50 Hz contains a resistance R = 3 k

\Omega

, an inductor of inductive reactance

X_L

= 250

\pi\Omega

and an unknown capacitor. The value of capacitance to maximize the average power should be : (Take

\pi^2

= 10)

(A)4 $\mu$ F
(B)25 $\mu$ F
(C)400 $\mu$ F
(D)40 $\mu$ F

Q100·PhysicsSingle correctJEE Main 2021

A 100 Ω resistance, a 0.1 μF capacitor and an inductor are connected in series across a 250 V supply at variable frequency. Calculate the value if inductance of inductor at which resonance will occur. Given that the resonant frequency is 60 Hz.

(A)7.03 × 10 $^{-5}$ H
(B)70.3 H
(C)70.3 mH
(D)0.70 H

Q101·PhysicsSingle correctJEE Main 2021

A 0.07 H inductor and a 12

\Omega

resistor are connected in series to a 220 V, 50 Hz ac source. The approximate current in the circuit and the phase angle between current and source voltage are respectively. [ Take

\pi

as

\frac{22}{7}

]

(A)88 A and $\tan^{-1}\left(\frac{11}{6}\right)$
(B)8.8 A and $\tan^{-1}\left(\frac{11}{6}\right)$
(C)0.88 A and $\tan^{-1}\left(\frac{11}{6}\right)$
(D)8.8 A and $\tan^{-1}\left(\frac{6}{11}\right)$

Q102·PhysicsNumericalJEE Main 2021

Two circuits are shown in the figure (a) & (b). At a frequency of ________ rad /s the average power dissipated in one cycle will be same in both the circuits.

Q103·PhysicsSingle correctJEE Main 2021

A

10\,\Omega

resistance is connected across 220 V

-

50 Hz AC supply. The time taken by the current to change from its maximum value to the rms value is :

(A)2.5 ms
(B)4.5 ms
(C)3.0 ms
(D)1.5 ms

Q104·PhysicsSingle correctJEE Main 2021

In a circuit consisting of a capacitance and a generator with alternating emf

E_g=E_{g_0}\sin\omega t

,

V_C

and

I_C

are the voltage and current. Correct phase diagram for such circuit is :

(A)(A)
(B)(B)
(C)(C)
(D)(D)

Q105·PhysicsSingle correctJEE Main 2021

Match List

-

I with List

-

II : Choose the correct answer from the options given below :

List-I	List-II
a. $\omega L>\frac{1}{\omega C}$	i.Current is in phase with emf
b. $\omega L=\frac{1}{\omega C}$	ii.Current lags behind the applied emf
c. $\omega L<\frac{1}{\omega C}$	iii.Maximum current occurs
d.Resonant frequency	iv.Current leads the emf

(A)(a) $-$ (iv); (b) $-$ (iii); (c) $-$ (ii); (d) $-$ (i)
(B)(a) $-$ (ii); (b) $-$ (i); (c) $-$ (iv); (d) $-$ (iii)
(C)(a) $-$ (iii); (b) $-$ (i); (c) $-$ (iv); (d) $-$ (ii)
(D)(a) $-$ (ii); (b) $-$ (i); (c) $-$ (iii); (d) $-$ (iv)

Q106·PhysicsSingle correctJEE Main 2021

For a series LCR circuit with

R = 100\,\Omega

,

L = 0.5\,mH

and

C = 0.1\,pF

connected across

220V - 50Hz

AC supply, the phase angle between current and supplied voltage and the nature of the circuit is :

(A) $\approx 90^\circ$ , predominantly inductive circuit
(B) $0^\circ$ , resonance circuit
(C) $\approx 90^\circ$ , predominantly capacitive circuit
(D) $0^\circ$ , resistive circuit

Q107·PhysicsNumericalJEE Main 2021

In an LCR series circuit, an inductor 30 mH and a resistor 1 Ω are connected to an Ac source of angular frequency 300 rad /s. The value of capacitance for which, the current leads the voltage by 45° is

\frac{1}{x} \times 10^{-3}

F. Then the value of x is ____________.

Q108·PhysicsNumericalJEE Main 2021

A series LCR circuit of

\mathrm{R} = 5\Omega, \mathrm{L} = 20\,\mathrm{mH}

and

\mathrm{C} = 0.5\,\mu\mathrm{F}

is connected across an AC supply of 250 V, having variable frequency. The power dissipated at resonance condition is _________

\times 10^{2}

W.

Q109·PhysicsSingle correctJEE Main 2021

In a series LCR resonance circuit, if we change the resistance only, from a lower to higher value :

(A)The bandwidth of resonance circuit will increase.
(B)The resonance frequency will increase.
(C)The quality factor will increase.
(D)The quality factor and the resonance frequency will remain constant.

Q110·PhysicsSingle correctJEE Main 2021

An AC source rated 220 V, 50 Hz is connected to a resistor. The time taken by the current to change from its maximum to the rms value is :

(A)2.5 ms
(B)25 ms
(C)2.5 s
(D)0.25 ms

Q111·PhysicsSingle correctJEE Main 2021

In a series LCR circuit, the inductive reactance (

X_L

) is 10 Ω and the capacitive reactance (

X_C

) is 4 Ω. The resistance (R) in the circuit is 6 Ω. The power factor of the circuit is :

(A) $\frac{1}{2}$
(B) $\frac{1}{2\sqrt{2}}$
(C) $\frac{1}{\sqrt{2}}$
(D) $\frac{\sqrt{3}}{2}$

Q112·PhysicsSingle correctJEE Main 2021

An AC current is given by

I = I_1 \sin\omega t + I_2 \cos\omega t

. A hot wire ammeter will give a reading :

(A) $\sqrt{\frac{I_1^2 - I_2^2}{2}}$
(B) $\sqrt{\frac{I_1^2 + I_2^2}{2}}$
(C) $\frac{I_1 + I_2}{\sqrt{2}}$
(D) $\frac{I_1 + I_2}{2\sqrt{2}}$

Q113·PhysicsSingle correctJEE Main 2021

What happens to the inductive reactance and the current in a purely inductive circuit if the frequency is halved ?

(A)Both, inductive reactance and current will be halved.
(B)Inductive reactance will be halved and current will be doubled.
(C)Inductive reactance will be doubled and current will be halved.
(D)Both, inducting reactance and current will be doubled.

Q114·PhysicsSingle correctJEE Main 2021

Match List-I with List-II Choose the most appropriate answer from the options given below :

List-I	List-II
a.Phase difference between current and voltage in a purely resistive AC circuit	i. $\frac{\pi}{2}$ ; current leads voltage
b.Phase difference between current and voltage in a pure inductive AC circuit	ii.zero
c.Phase difference between current and voltage in a pure capacitive AC circuit	iii. $\frac{\pi}{2}$ ; current lags voltage
d.Phase difference between current and voltage in an LCR series circuit	iv. $\tan^{-1}\left(\frac{X_{C} - X_{L}}{R}\right)$

(A)(a)−(i),(b)−(iii),(c)−(iv),(d)−(ii)
(B)(a)−(ii),(b)−(iv),(c)−(iii),(d)−(i)
(C)(a)−(ii),(b)−(iii),(c)−(iv),(d)−(i)
(D)(a)−(ii),(b)−(iii),(c)−(i),(d)−(iv)

Q115·PhysicsNumericalJEE Main 2021

A sinusoidal voltage of peak value 250 V is applied to a series LCR circuit, in which R = 8Ω, L = 24 mH and C = 60µF. The value of power dissipated at resonant condition is 'x' kW. The value of x to the nearest integer is ________.

Q116·PhysicsSingle correctJEE Main 2021

An RC circuit as shown in the figure is driven by a AC source generating a square wave. The output wave pattern monitored by CRO would look close to :

(A)(1)
(B)(2)
(C)(3)
(D)(4)

Q117·PhysicsSingle correctJEE Main 2021

For the given circuit, comment on the type of transformer used :

(A)Auxilliary transformer
(B)Auto transformer
(C)Step-up transformer
(D)Step down transformer

Q118·PhysicsSingle correctJEE Main 2021

An alternating current is given by the equation i=i

_{1}

sinωt + i

_{2}

cosωt. The rms current will be :

(A) $\frac{1}{2}\left(i_{1}^{2} + i_{2}^{2}\right)^{\frac{1}{2}}$
(B) $\frac{1}{\sqrt{2}}\left(i_{1}^{2} + i_{2}^{2}\right)^{\frac{1}{2}}$
(C) $\frac{1}{\sqrt{2}}\left(i_{1} + i_{2}\right)^{2}$
(D) $\frac{1}{\sqrt{2}}\left(i_{1} + i_{2}\right)$

Q119·PhysicsSingle correctJEE Main 2021

Find the peak current and resonant frequency of the following circuit (as shown in figure)

(A)0.2 A and 100 Hz
(B)2 A and 50 Hz
(C)2 A and 100 Hz
(D)0.2 A and 50 Hz

Q120·PhysicsNumericalJEE Main 2021

In a series LCR resonant circuit, the quality factor is measured as 100. If the inductance is increased by two fold and resistance is decreased by two fold, then the quality factor after this change will be ____________.

Q121·PhysicsSingle correctJEE Main 2021

An LCR circuit contains resistance of 110Ω and a supply of 220 V at 300 rad/s angular frequency. If only capacitance is removed from the circuit, current lags behind the voltage by 45

^{o}

. If on the other hand, only inductor is removed the current leads by 45

^{o}

with the applied voltage. The rms current flowing in the circuit will be:

(A)2.5A
(B)2A
(C)1A
(D)1.5 A

Q122·PhysicsSingle correctJEE Main 2021

The angular frequency of alterlating current in a L-C-R circuit is 100 rad/s. The components connected are shown in the figure. Find the value of inductance of the coil and capacity of condenser.

(A)0.8 H and 250 $\mu$ F
(B)0.8 H and 150 $\mu$ F
(C)1.33 H and 250 $\mu$ F
(D)1.33 H and 150 $\mu$ F

Q123·PhysicsNumericalJEE Main 2021

A transmitting station releases waves of wavelength 960 m. A capacitor of 256

\mu

F is used in the resonant circuit. The self inductance of coil necessary for resonance is ______

\times 10^{-8}

H.

Q124·PhysicsNumericalJEE Main 2021

A common transistor radio set requires 12 V (D.C.) for its operation. The D.C. source is constructed by using a transformer and a rectifier circuit, which are operated at 220 V (A.C.) on standard domestic A.C. supply. The number of turns of secondary coil are 24, then the number of turns of primary are ________.

Q125·PhysicsNumericalJEE Main 2021

A resonance circuit having inductance and resistance

2 \times 10^{-4}

H and 6.28

\Omega

respectively oscillates at 10 MHz frequency. The value of quality factor of this resonator is__________. [

\pi

= 3.14]

Q126·PhysicsNumericalJEE Main 2021

A series LCR circuit is designed to resonate at an angular frequency

\omega_{0} = 10^{5}\,\mathrm{rad/s}

. The circuit draws 16W power from 120 V source at resonance. The value of resistance ‘R’ in the circuit is ________

\Omega

.

Q127·PhysicsNumericalJEE Main 2020

In a series LR circuit, power of 400 W is dissipated from a source of 250 V, 50 Hz. The power factor of the circuit is 0.8. In order to bring the power factor to unity, a capacitor of value C is added in series to the L and R. Taking the value of C as

\left(\frac{n}{3\pi}\right)

μF, then value of 'n' is ______.

Q128·PhysicsSingle correctJEE Main 2020

A 750 Hz, 20 V (rms) source is connected to a resistance of 100 Ω an inductance of 0.1803 H and a capacitance of 10 μF all in series. The time in which the resistance (heat capacity 2 J/°C) will get heated by 10°C. (assume no loss of heat to the surroundings) is close to:

(A)348 s
(B)365 s
(C)418 s
(D)245 s

Q129·PhysicsSingle correctJEE Main 2020

In LC circuit the inductance L = 40 mH and capacitance C = 100 μF. If a voltage V(t) = 10 sin (314 t) is applied to the circuit, the current in the circuit is given as

(A)5.2 cos 314 t
(B)0.52 sin 314 t
(C)0.52 cos 314 t
(D)10 cos 314 t

Q130·PhysicsSingle correctJEE Main 2020

A LCR circuit behaves like a damped harmonic oscillator. Comparing it with a physical spring-mass damped oscillator having damping constant 'b', the connect equivalence would be:

(A)L $\leftrightarrow$ $\frac{1}{b}$ , C $\leftrightarrow$ $\frac{1}{m}$ , R $\leftrightarrow$ $\frac{1}{k}$
(B)L $\leftrightarrow$ k, C $\leftrightarrow$ b, R $\leftrightarrow$ m
(C)L $\leftrightarrow$ m, C $\leftrightarrow$ $\frac{1}{k}$ , R $\leftrightarrow$ b
(D)L $\leftrightarrow$ m, C $\leftrightarrow$ k, R $\leftrightarrow$ b

Q131·PhysicsSingle correctJEE Main 2019

A transformer consisting of 300 turns in the primary and 150 turns in the secondary gives output power of 2.2 kW. If the current in the secondary coils is 10 A, then the input voltage and current in the primary coil are:

(A)440 V and 5 A
(B)440 and 20 A
(C)220 V and 20 A
(D)220 V and 10 A

Q132·PhysicsSingle correctJEE Main 2019

A circuit connected to an ac source of emf

e = e_0\sin(1000t)

with t in seconds, gives a phase difference of

\dfrac{\pi}{4}

between the emf e and current i. Which of the following circuits will exhibit this?

(A)RC circuit with $R = 1k\Omega$ and $C = 1\mu F$
(B)RL circuit with $R = 1k\Omega$ and $L = 10mH$
(C)RL circuit with $R = 1k\Omega$ and $L = 1mH$
(D)RC circuit with $R = 1k\Omega$ and $C = 10\mu F$

Q133·PhysicsSingle correctJEE Main 2019

An alternating voltage

v(t) = 220 \sin 100\pi t

volt is applied to a purely resistive load of

50\,\Omega

. The time taken for the current to rise from half of the peak value of the peak value is:

(A)2.2 ms
(B)3.3 ms
(C)5 ms
(D)7.2 ms

Q134·PhysicsSingle correctJEE Main 2019

A power transmission line feeds input power at 2300 V to a step down transformer with its primary windings having 4000 turns. The output power is delivered at 230 V by the transformer. If the current in the primary of the transformer is 5A and its efficiency is 90%, the output current would be:

(A)50 A
(B)45 A
(C)35 A
(D)25 A

Q135·PhysicsSingle correctJEE Main 2019

A series AC circuit containing an inductor (20 mH), a capacitor (120

\mu F

) and a resistor (60

\Omega

) is driven by an AC source of 24 V/50 Hz. The energy dissipated in the circuit in 60 s is:

(A) $5.65 \times 10^{2}$ J
(B) $2.26 \times 10^{3}$ J
(C) $5.17 \times 10^{2}$ J
(D) $3.39 \times 10^{3}$ J

Q136·PhysicsMultiple correctJEE Advanced 2017

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?

(A)The frequency at which the current will be in the phase with the voltage is independent of R.
(B)At $\omega \sim 0$ the current flowing through the circuit becomes nearly zero.
(C)At $\omega >> 10^{6}$ $rad.s^{-1}$ , the circuit behave like a capacitor.
(D)The current will be in phase with the voltage if $\omega = 10^{4}$ rad. $s^{-1}$

Q137·PhysicsMultiple correctJEE Advanced 2017

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 + \dfrac{2\pi}{3}\right)

and

V_{Z} = V_{0}\sin\!\left(\omega t + \dfrac{4\pi}{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

(A) $V_{XY}^{rms} = V_{0}\sqrt{\dfrac{3}{2}}$
(B) $V_{YZ}^{rms} = V_{0}\sqrt{\dfrac{1}{2}}$
(C) $V_{XY}^{rms} = V_{0}$
(D)independent of the choice of the two terminals

Q138·PhysicsMultiple correctJEE Advanced 2014

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) = I_0 \cos (\omega t)

, with

I_0 = 1 \text{ A}

and

\omega = 500 \text{ rad/s}

starts flowing in it with the initial direction shown in the figure. At

t = \frac{7\pi}{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\text{F}

,

R = 10 \Omega

and the battery is ideal with emf of

50 \text{ V}

, identify the correct statement(s).

(A)Magnitude of the maximum charge on the capacitor before $t = \frac{7\pi}{6\omega}$ is $1 \times 10^{-3} \text{ C}$ .
(B)The current in the left part of the circuit just before $t = \frac{7\pi}{6\omega}$ is clockwise.
(C)Immediately after $A$ is connected to $D$ , the current in $R$ is $10 \text{ A}$ .
(D) $Q = 2 \times 10^{-3} \text{ C}$ .

Q139·PhysicsSingle correctJEE Advanced 2013

A thermal power plant produces electric power of

600\ \mathrm{kW}

at

4000\ \mathrm{V}

, which is to be transported to a place

20\ \mathrm{km}

away from the power plant for consumers' usage. It can be transported either directly with a cable of large current carrying capacity or by using a combination of step-up and step-down transformers at the two ends. The drawback of the direct transmission is the large energy dissipation. In the method using transformers, the dissipation is much smaller. In this method, a step-up transformer is used at the plant side so that the current is reduced to a smaller value. At the consumers' end, a step-down transformer is used to supply power to the consumers at the specified lower voltage. It is reasonable to assume that the power cable is purely resistive and the transformers are ideal with the power factor unity. All the currents and voltage mentioned are rms values. If the direct transmission method with a cable of resistance

0.4\ \Omega\ \mathrm{km^{-1}}

is used, the power dissipation (in %) during transmission is

(A)20
(B)30
(C)40
(D)50

Q140·PhysicsSingle correctJEE Advanced 2013

A thermal power plant produces electric power of

600\ \mathrm{kW}

at

4000\ \mathrm{V}

, which is to be transported to a place

20\ \mathrm{km}

away from the power plant for consumers' usage. It can be transported either directly with a cable of large current carrying capacity or by using a combination of step-up and step-down transformers at the two ends. The drawback of the direct transmission is the large energy dissipation. In the method using transformers, the dissipation is much smaller. In this method, a step-up transformer is used at the plant side so that the current is reduced to a smaller value. At the consumers' end, a step-down transformer is used to supply power to the consumers at the specified lower voltage. It is reasonable to assume that the power cable is purely resistive and the transformers are ideal with the power factor unity. All the currents and voltage mentioned are rms values. 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 to the consumers has to be supplied at

200\ \mathrm{V}

, the ratio of the number of turns in the primary to that in the secondary in the step-down transformer is

(A) $200 : 1$
(B) $150 : 1$
(C) $100 : 1$
(D) $50 : 1$

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