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Alternating Current — NEET UG Physics PYQs

366 previous year questions from Alternating Current with answers and solutions. Numbered list, year tags, and one-tap solutions — built for serious JEE / NEET practice.

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1

A step down transformer connected to an a.c. mains of 220 V is made to operate at 5.5 V, 44 W lamp. The current in the primary circuit is (Ignore power losses)

MHT CET Medical 2026 Solution View → 2

Which phasor diagram represents LCR circuit at resonance?

MHT CET Medical 2026 Solution View → 3

For an R-L series circuit, the power factor is 3 2 , for R-L frequency f Hz. If the frequency doubles, the new power factor will be

MHT CET Medical 2026 Solution View → 4

In an AC circuit, the current is I = 100 (5t) A. The value of I_ rms is

MHT CET Medical 2026 Solution View → 5

The ratio of power factor of purely resistive circuit to purely reactive circuit is ( 0^ = 1 and 90^ = 0 )

MHT CET Medical 2026 Solution View → 6

In an LCR series circuit, at resonance,

MHT CET Medical 2026 Solution View → 7

In an AC circuit, E and I are given by E = 150 (150t) V and I = 150 (150t + 3 ) A. The power dissipated in the circuit is (60)^ = 1/2

MHT CET Medical 2026 Solution View → 8

A series LCR circuit is connected across a source E of e.m.f. E=15 (50 t- 3 ) . The current from the supply is I=5 (50 t+ 6 ) . The impedance of the circuit and the phase differenc

MHT CET Medical 2026 Solution View → 9

The alternating voltage is given by V=V₀ ( t+ 6 ) . When will the voltage be maximum for the first time? (90)^ =1

MHT CET Medical 2026 Solution View → 10

An alternating voltage is given as, E=100 2 100t This voltage E is applied to a capacitor of 1 F . The current reading in an a.c. ammeter in mA is

MHT CET Medical 2026 Solution View → 11

In an L-C-R series, AC circuit at resonance,

MHT CET Medical 2026 Solution View → 12

If a coil of inductance L and resistance R is connected to AC source with voltage V and angular frequency and current I, then the inductance L is

MHT CET Medical 2026 Solution View → 13

The potential differences across the resistor, capacitor and inductor are 80 V, 40 and 100 V respectively in series LCR circuit. The power factor of this circuit is

MHT CET Medical 2026 Solution View → 14

In a series LCR circuit, the resistance (R), inductive reactance X_L = 2R and capacitive reactance X_C = R . The impedance of the circuit is

MHT CET Medical 2026 Solution View → 15

If the r.m.s. current in an a.c. circuit is 5 A, having frequency 50 Hz. The value of current 1 300 s after its value becomes zero (in A) is ( /3) = (3)^ 0.5 /2

MHT CET Medical 2026 Solution View → 16

In the LCR series circuit, an alternating e.m.f. e and current i are given by the equation e = 100 (100t) ,V and i = 100 (100t + 3 )mA . The average power dissipated in the circuit

MHT CET Medical 2026 Solution View → 17

In a series LCR circuit R = X_L = 2X_C . The impedance of the circuit and phase difference between 'V' and 'I' respectively will be

MHT CET Medical 2026 Solution View → 18

An alternating current is given by i = i₁ t - i₂ t . The rms current is given by

MHT CET Medical 2026 Solution View → 19

A series LCR circuit is connected to a source of alternating e.m.f. of 50 V. The potential difference across inductor and capacitor is 80 V and 50 V respectively. The potential dif

MHT CET Medical 2026 Solution View → 20

Consider the statements on capacitive reactance. Statement I: As capacitance increases, the capacitive reactance also increases. Statement II: The capacitive reactance is independe

MHT CET Medical 2026 Solution View → 21

In a step-up transformer, if the voltage in the secondary is increased, then the current in the primary:

MHT CET Medical 2026 Solution View → 22

At resonance, the LC parallel resonant circuit

MHT CET Medical 2026 Solution View → 23

A series LCR circuit is connected to an AC source of 220 V, 50 Hz. The circuit contains resistance of 100 , capacitor of capacitive reactance X_C and inductor of inductive reactanc

MHT CET Medical 2026 Solution View → 24

An a.c. source is connected to a capacitor 'C'. Due to increase in its operating frequency

MHT CET Medical 2026 Solution View → 25

In series LCR circuit, R = 10 and impedance is 30 . An rms voltage 210 V is applied across the circuit. The true power consumed in A.C. circuit in watt is

MHT CET Medical 2026 Solution View → 26

A series L-C-R circuit is connected to a source of alternating emf of 50 V . The potential difference across inductor and capacitor is 80 V and 50 V respectively. The potential dif

MHT CET Medical 2026 Solution View → 27

When a 60 mH inductor and resistor are connected in series with an AC source, the voltage leads the current by 60^ . If the inductor is replaced by a 0.5 F capacitor, the voltage l

MHT CET Medical 2026 Solution View → 28

When a.c. source is connected across a resistance, the correct phasor relation between the current ( i_R ) and emf ( e_R ) is shown in figure

MHT CET Medical 2026 Solution View → 29

The output of a step-down transformer is measured to be 56 V when connected to 14 W light bulb. The value of peak current is (in A)

MHT CET Medical 2026 Solution View → 30

An alternating voltage given as, E = 100 2 (100t) volt is applied to a capacitor of 1 F . The current reading of the ammeter will be equal to

MHT CET Medical 2026 Solution View → 31

The r.m.s value of current in a 50 Hz A.C. circuit is 10 A. The average value of A.C. current over a cycle is

MHT CET Medical 2026 Solution View → 32

In a series LCR circuit, the inductance L is 10 mH, capacitance C is 100 F and resistance R is 20 . The frequency at which impedance is 20 , is

MHT CET Medical 2026 Solution View → 33

A resistance 'R' draws a power 'P' when connected to A.C. source. If an inductor is now placed in series with the resistance, such that the impedance of the circuit becomes 'Z', th

MHT CET Medical 2026 Solution View → 34

In series LCR circuit the alternating emf 'e' and the current 'i' are given by the equations e = e₀ t , i = i₀ ( t + 6 ) . The average power dissipated in the circuit over a one co

MHT CET Medical 2026 Solution View → 35

An ac circuit contains a resistance of 1 k , a capacitor of 0.1 F and an inductor of 1 mH connected in series. The resonance frequency of the circuit is approximately :

NEET 2026 Solution View → 36

The peak value of an alternating current is 5 A and frequency is 60 Hz. How long will the current, starting from zero, take to reach the peak value ?

NEET 2026 Solution View → 37

An ac voltage V=220 (2 10^3 t) Volt is applied to a series LCR circuit. Then the current amplitude in this circuit is : (Given : L=10 mH, C=25 , F, R=100 , )

NEET 2026 Solution View → 38

To an ac power supply of 220 V at 50 Hz , a resistor of 20 , a capacitor of reactance 25 and an inductor of reactance 45 are connected is series. The corresponding current in the c

NEET 2025 Solution View → 39

A step up transformer is connected to an ac mains supply of 220 V to operate at 11000 ~V , 88 watt. The current in the secondary circuit, ignoring the power loss in the transformer

NEET 2024 Solution View → 40

The amplitude of the charge oscillating in a circuit decreases exponentially as Q=Q₀ e^ -R t 2 L , where Q₀ is the charge at t=0 ~s . The time at which charge amplitude decreases t

NEET 2024 Solution View → 41

In the circuit shown below, the inductance L is connected to an ac source. The current flowing in the circuit is I=I₀ t . The voltage drop (V_L ) across L is

NEET 2024 Solution View → 42

A 10 F capacitor is connected to a 210 ~V , 50 ~Hz source as shown in figure. The peak current in the circuit is nearly ( =3.14) :

NEET 2024 Solution View → 43

In an ideal transformer, the turns ratio is N_P N_S = 1 2 . The ratio V_S: V_P is equal to (the symbols carry their usual meaning) :

NEET 2024 Solution View → 44

An ac source is connected in the given circuit. The value of will be

NEET 2023 Solution View → 45

The maximum power is dissipated for an ac in a/an

NEET 2023 Solution View → 46

For very high frequencies, the effective impedance of the circuit (shown in the figure) will be

NEET 2023 Solution View → 47

A 12   V ,   60   W lamp is connected to the secondary of a step down transformer, whose primary is connected to ac mains of 220   V . Assuming the transformer

NEET 2023 Solution View → 48

In a series   L C R circuit, the inductance   L is 10   mH , capacitance C is 1   μF and resistance R is 100   Ω . The frequency at which resonan

NEET 2023 Solution View → 49

An ac source is connected to a capacitor C . Due to decrease in its operating frequency:

NEET 2023 Solution View → 50

The net impedance of circuit (as shown in figure) will be:

NEET 2023 Solution View → 51

If Z₁ and Z₂ are the impedances of the given circuits (a) and (b) as shown in figures, then choose the correct option.

NEET 2023 Solution View → 52

An inductor of inductance 2 mH is connected to a 220 ~V , 50 ~Hz a.c. source. Let inductive reactance in the circuit is X₁ . If a 220 ~V d.c. source replaces the a.c. source in the

NEET 2022 Solution View → 53

Given below are two statements: Statement-I: In an a.c. circuit, the current through a capacitor leads the voltage across it. Statement-II: In a.c. circuits containing pure capacit

NEET 2022 Solution View → 54

The peak voltage of the ac source is equal to

NEET 2022 Solution View → 55

A series LCR circuit with inductance 10   H , capacitance 10   μ F , resistance 50   Ω is connected to an AC source of voltage, V = 200 sin 100 t volt. If

NEET 2022 Solution View → 56

A standard filament lamp consumes 100 ~W when connected to 200 ~V a.c. mains supply. The peak current through the bulb will be :

NEET 2022 Solution View → 57

An inductor of inductance L , a capacitor of capacitance C and a resistor of resistance R are connected in series to an ac source of potential difference V volt as shown in figure.

NEET 2021 Solution View → 58

A step down transformer connected to an ac mains supply of 220   V is made to operate at 11   V ,   44   W lamp. Ignoring power losses in the transformer, what

NEET 2021 Solution View → 59

A series L - C - R circuit containing 5 . 0   H inductor, 80   μ F capacitor and 40   Ω resistor is connected to 230   V variable frequency ac source.

NEET 2021 Solution View → 60

A light bulb and an inductor coil are connected to an ac source through a key as shown in the figure below. The key is closed and after sometime an iron rod is inserted into the in

NEET 2020 Solution View → 61

A series L C R circuit is connected to an ac voltage source. When L is removed from the circuit, the phase difference between current and voltage is π 3 . If instead C is remo

NEET 2020 Solution View → 62

A 40   μF capacitor is connected to a 200   V , 50   Hz AC supply. The rms value of the current in the circuit is, nearly:

NEET 2020 Solution View → 63

In a transformer number of turns in primary circuit is 500 and in secondary circuit number of turns is 10 . The load resistance is 10 and voltage of secondary coil is 50 ~V . Then

AIIMS 2019 Solution View → 64

In a L C R oscillatory circuit, find the energy stored in inductor at resonance if voltage of source is 10 ~V , resistance is 10 and inductance =1 H .

AIIMS 2019 Solution View → 65

In LCR series circuit, source voltage is 120 ~V and voltage across inductor 50 ~V . If voltage drop across resistance is 40 ~V , then determine voltage in capacitor.

AIIMS 2019 Solution View → 66

Assertion : A capacitor of suitable capacitance can be used in an AC circuit in place of the choke coil. Reason : A capacitor blocks DC and allows AC only.

AIIMS 2019 Solution View → 67

Find resonance frequency in the given circuit

JIPMER 2019 Solution View → 68

Find the current drawn from the battery just after the switch is closed.

JIPMER 2019 Solution View → 69

A circuit when connected to an AC source of 12 ~V gives a current of 0.2 ~A . The same circuit when connected to a DC source of 12 ~V , gives a current of 0.4 ~A . The circuit is

NEET 2019 Solution View → 70

Which of the following acts as a circuit protective device?

NEET 2019 Solution View → 71

The voltage across a pure inductor is represented in figure. Which one of the following curves in the figure will represent the current?

AIIMS 2018 Solution View → 72

An electric bulb has a rated power of 50 ~W at 100 ~V . If it is used on an AC source of 200 ~V , 50 ~Hz , a choke has to be used in series with it. This choke should have an induc

AIIMS 2018 Solution View → 73

A series combination of resistor (R) and capacitor (C) is connected to an AC source of angular frequency . Keeping the voltage same, if the frequency is changed to 3 , the current

AIIMS 2018 Solution View → 74

In a L-C circuit, angular frequency at resonance is . What will be the new angular frequency when inductor's inductance is made two times and capacitor's capacitance is made four t

JIPMER 2018 Solution View → 75

The magnetic potential energy stored in a certain inductor is 25   mJ , when the current in the inductor is 60   mA . This inductor is of inductance

NEET 2018 Solution View → 76

An inductor 20 mH, capacitor 100   μF and a resistor 50  Ω are connected in series across a source of emf, V =   10 sin ⁡( 314 t ⁡) . The power

NEET 2018 Solution View → 77

A transformer with efficiency 80 % works at 4 ~kW and 100 ~V . If the secondary voltage is 200 ~V , then the primary and secondary currents are respectively

AIIMS 2017 Solution View → 78

In an L C R circuit as shown in figure, both switches are open initially. Now switch S₁ is closed, S₂ kept open. ( q is charge on the capacitor and =R C is capacitive time constant

AIIMS 2017 Solution View → 79

Figure shows a circuit contains three identical resistors with resistance R = 9.0   Ω each, two identical inductors with inductance L = 2.0    mH each, and an

NEET 2017 Solution View → 80

Assertion : At resonance, L C R series circuit have a minimum current. Reason : At resonance, in LCR series circuit, the current and e.m.f are not in phase with each other.

AIIMS 2016 Solution View → 81

A series resonant L C R circuit has a quality factor (Q-factor) 0.4 . If R=2 k , C=0.1 F , then the value of inductance is

AIIMS 2016 Solution View → 82

A transformer having efficiency of 75 % is working on 220 V and 4.4 kW power supply. If the current in the secondary coil is 5 A . What will be the voltage across secondary coil an

JIPMER 2016 Solution View → 83

An L-C-R series circuit with a resistance of 100 is connected to 200 V (AC source) and angular frequency 300 rad / s . When only the capacitor is removed, then the current lags beh

JIPMER 2016 Solution View → 84

Which of the following combinations should be selected for better tuning of an LCR circuit used for communication?

NEET 2016 Solution View → 85

The potential differences across the resistance, capacitance, and inductance are 80   V ,   40   V and 100   V , respectively in an LCR circuit. The power facto

NEET 2016 Solution View → 86

A 100   Ω resistance and a capacitor of 100   Ω reactance are connected in series across a 220 V source. When the capacitor is 50 % charged, the peak value of t

NEET 2016 Solution View → 87

An inductor 20   mH , a capacitor 50  μ F and a resistor 40   Ω are connected in series across a source of emf V = 10   sin   ⁡ 340  

NEET 2016 Solution View → 88

A small signal voltage V t = V 0 sin ⁡ ω t is applied across an ideal capacitor C :

NEET 2016 Solution View → 89

A coil of inductance 8 H is connected to a capacitor of capacitance 0.02 F . To what wavelength is this circuit tuned?

AIIMS 2015 Solution View → 90

An inductor (L=20 H ) , a resistor (R=100 ) and a battery (E=10 ~V ) are connected in series. After a long time, the circuit is short-circuited and then the battery is disconnected

JIPMER 2015 Solution View → 91

A resistance R draws power P when connected to an AC source. If an inductance is now placed in series with the resistance, such that the impedance of the circuit becomes Z , the po

NEET 2015 Solution View → 92

A series R-C circuit is connected to an alternating voltage source. Consider two situations: a. When capacitor is air filled. b. When capacitor is mica filled. Current through resi

NEET 2015 Solution View → 93

The most suitable metal for making electromagnets and transformer cores is

AIIMS 2014 Solution View → 94

An inductive circuit contains a resistance of 10 and an inductance of 2 H . If an AC voltage of 120 ~V and frequency 60 ~Hz is applied to this circuit, the current would be nearly

AIIMS 2014 Solution View → 95

If we change the value of R , then

JIPMER 2014 Solution View → 96

Real power consumption in a circuit is least when it contains.

JIPMER 2014 Solution View → 97

A transformer having efficiency of 90 % is working on 200   V and 3   k W power supply. If the current in the secondary coil is 6   A the voltage across the secondar

NEET 2014 Solution View → 98

In an oscillating system, a restoring force is a must. In an L-C circuit, restoring force is provide by

AIIMS 2013 Solution View → 99

220 ~V , 50 ~Hz , AC source is connected to an inductance of 0.2 H and a resistance of 20 in series. What is the current in the circuit?

JIPMER 2013 Solution View → 100

The primary winding of transformer when connected to a d c battery of 10 Volt draws a current of 1 ~mA . The number of turns of the primary and secondary windings are 50 and 100 re

NEET 2013 Solution View → 101

A coil of self-inductance L is connected in series with a bulb B and an A C source. Brightness of the bulb decreases when

NEET 2013 Solution View → 102

In an A C circuit, voltage V=V₀ t and inductor L is connected across the circuit. Then the instantaneous power will be

AIIMS 2012 Solution View → 103

In a given series L C R circuit R=4 , X_L=5 and X_C=8 , the current

AIIMS 2012 Solution View → 104

Which of the following parameter in the series LCR circuit is analogous to driving force F(t) in mechanics?

AIIMS 2012 Solution View → 105

An electric bulb has a rated power of 50 W at 100 V . If it is used on an AC source 200 ~V , 50 ~Hz , a choke has to be used in series with it. This choke should have an inductance

JIPMER 2012 Solution View → 106

In an L-C-R circuit inductance is changed from L to L / 2 . To keep the same resonance frequency, C should be changed to

JIPMER 2012 Solution View → 107

The current (I) in the inductance is varying with time according to the plot shown in figure. Which one of the following is the correct variation of voltage with time in the coil?

NEET 2012 Solution View → 108

The instantaneous values of alternating current and voltages in a circuit are given as aligned & i= 1 2 (100 t) ampere & e= 1 2 (100 t+ / 3) volt aligned The average power in Watts

NEET 2012 Solution View → 109

In an electrical circuit R, L, C and an AC voltage source are all connected in series. When L is removed from the circuit, the phase difference between the voltage and the current

NEET 2012 Solution View → 110

What is the mechanical equivalent of spring constant k in LC oscillating circuit?

AIIMS 2011 Solution View → 111

In series L C R circuit, the phase difference between applied voltage and current is

AIIMS 2011 Solution View → 112

Voltage in the secondary coil of a transformer does not depend upon

JIPMER 2011 Solution View → 113

A choke is preferred to a resistance for limiting current in AC circuit because

JIPMER 2011 Solution View → 114

In an AC circuit an alternating voltage e=200 2 100 t volt is connected to a capacitor of capacity 1 F . The rms value of the current in the circuit is

NEET 2011 Solution View → 115

An AC voltage is applied to a resistance R and an inductor L in series. If R and the inductive reactance are both equal to 3 , the phase difference between the applied voltage and

NEET 2011 Solution View → 116

The rms value of potential difference V shown in the figure is

NEET 2011 Solution View → 117

A coil has resistance 30 and inductive reactance 20 at 50 ~Hz frequency. If an AC source of 200 ~V , 100 ~Hz , is connected across the coil, the current in the coil will be

NEET 2011 Solution View → 118

Alternating current cannot be measured by D.C. ammeter because

AIIMS 2010 Solution View → 119

The core of any transformer is laminated so as to

AIIMS 2010 Solution View → 120

In a series L-C-R circuit, resistance R=10 and the impedance Z=10 . The phase difference between the current and the voltage is

JIPMER 2010 Solution View →
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