What does Electromagnetic Induction and Alternating Currents cover for NEET Physics?

14 lessons: Alternating Currents, Eddy Currents, Faraday's Law, Induced EMF Current, LCR Series Circuit, Lenz's Law, Mutual Inductance, Peak RMS AC, Power in AC, Reactance Impedance, Resonance LCR, Self Inductance, Transformer and Wattless Current.

How often has Electromagnetic Induction and Alternating Currents come up in NEET past papers?

Our set of verified past papers has 20 questions from this unit, from NEET 2021, 2022, 2023, 2024, 2025 and 2026. Each is answered against the official NTA key.

Electromagnetic Induction and Alternating Currents

14 lessons

Topic index in NCERT order

14 of 14 lessons by the NCERT chapter they teach from, in book order. The page is the first printed page of your NCERT book the lesson cites; PYQs are the past NEET questions on that topic.

Alternating Currents

8 MCQs1 revision cardWorked example

Easy Recall (3)Direct Application (3)Concept Trap (1)Calculation (1)

Eddy Currents

8 MCQsWorked example

Easy Recall (2)Concept Trap (4)Direct Application (1)Calculation (1)

Faraday's Law

8 MCQs1 PYQs2 revision cardsWorked example

Easy Recall (3)Direct Application (3)Calculation (2)

Induced EMF Current

8 MCQs1 PYQs1 revision cardWorked example

Easy Recall (2)Concept Trap (1)Direct Application (3)Calculation (2)

LCR Series Circuit

8 MCQs2 PYQs1 revision cardWorked example

Easy Recall (3)Direct Application (3)Concept Trap (1)Calculation (1)

Lenz's Law

8 MCQs1 PYQs1 revision cardWorked example

Easy Recall (3)Direct Application (3)Concept Trap (1)Calculation (1)

Mutual Inductance

8 MCQs4 revision cardsWorked example

Easy Recall (3)Direct Application (3)Concept Trap (1)Calculation (1)

Peak RMS AC

8 MCQs1 PYQs1 revision cardWorked example

Easy Recall (2)Concept Trap (2)Direct Application (2)Calculation (2)

Power in AC

8 MCQs1 revision cardWorked example

Easy Recall (3)Direct Application (3)Concept Trap (1)Calculation (1)

Reactance Impedance

8 MCQs2 PYQs3 revision cardsWorked example

Easy Recall (3)Direct Application (3)Concept Trap (1)Calculation (1)

Resonance LCR

8 MCQs4 PYQs2 revision cardsWorked example

Easy Recall (3)Direct Application (3)Concept Trap (2)

Self Inductance

8 MCQs4 PYQs2 revision cardsWorked example

Easy Recall (3)Direct Application (3)Calculation (2)

Transformer

8 MCQs3 PYQs1 revision cardWorked example

Easy Recall (3)Direct Application (3)Calculation (1)Concept Trap (1)

Wattless Current

8 MCQs1 revision cardWorked example

Easy Recall (3)Direct Application (3)Calculation (2)

Past-paper questions from this unit

20 questions from NEET 2021, 2022, 2023, 2024, 2025, 2026. Answers verified against NTA official keys.

By year in our set: 2021 (2) · 2022 (4) · 2023 (5) · 2024 (3) · 2025 (2) · 2026 (4)

Lesson: Self Inductance

NEET 2026

Two identical inductors are connected in two different configurations P and Q, where a time varying current I(t) is flowing, as shown in the figure. The induced emf between points a and b for configuration P is E_P and that for configuration Q is E_Q. The ratio E_P/E_Q is : [Neglect the effect of mutual inductance.]

11/4

21/2

NTA Answer: Option 4(final)

Report an error · Every fix is public: corrections log

Lesson: Self Inductance

NEET 2026

Consider a long solenoid of length l and radius r. If n is the number of turns per unit length and μ₀ is the permeability of free space, the inductance of the solenoid is :

1μ₀πn²r²l

2μ₀n²r²l

3(μ₀/2π)n²r²l

42μ₀πn²r²l

NTA Answer: Option 1(final)

Report an error · Every fix is public: corrections log

Lesson: Resonance LCR

NEET 2026

An ac voltage V = 220 sin(2 × 10³ t) Volt is applied to a series LCR circuit. Then the current amplitude in this circuit is : (Given : L = 10 mH, C = 25 μF, R = 100 Ω)

12.2 A

25.5 A

311.0 A

422.0 A

NTA Answer: Option 1(final)

Report an error · Every fix is public: corrections log

Lesson: Induced EMF Current

NEET 2026

A conducting loop of finite resistance lies on the x-y plane. There is a constant magnetic field in the z direction. The area of the loop varies with time t, as A = A₀(1 + sin t) in appropriate units. The figure that correctly indicates the qualitative behaviour of the power P dissipated in the loop as a function of time is :

NTA Answer: Option 2(final)

Report an error · Every fix is public: corrections log

Lesson: LCR Series Circuit

NEET 2025

To an ac power supply of 220 V at 50 Hz, a resistor of 20 Ω, a capacitor of reactance 25 Ω and an inductor of reactance 45 Ω are connected in series. The corresponding current in the circuit and the phase angle between the current and the voltage is, respectively

115.6 A and 45°

27.8 A and 30°

37.8 A and 45°

415.6 A and 30°

NTA Answer: Option 3(final)

Report an error · Every fix is public: corrections log

Lesson: Self Inductance

NEET 2025

AB is a part of an electrical circuit (see figure). The potential difference “V A – VB”, at the instant when current i = 2 A and is increasing at a rate of 1 amp/second is:

110 volt

25 volt

36 volt

49 volt

NTA Answer: Option 1(final)

Report an error · Every fix is public: corrections log

Lesson: Transformer

NEET 2024Revised key

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) :

11 : 2

22 : 1

31 : 1

41 : 4

NTA Answer: Option 2(revised_final)

Report an error · Every fix is public: corrections log

Lesson: Lenz's Law

NEET 2024Revised key

In the above diagram, a strong bar magnet is moving towards solenoid-2 from solenoid-1. The direction of induced current in solenoid-1 and that in solenoid-2, respectively, are through the directions:

1AB and DC

2BA and CD

3AB and CD

4BA and DC

NTA Answer: Option 1(revised_final)

Report an error · Every fix is public: corrections log

Lesson: Reactance Impedance

NEET 2024Revised key

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

10.58 A

20.93 A

31.20 A

40.35 A

NTA Answer: Option 2(revised_final)

Report an error · Every fix is public: corrections log

Lesson: Reactance Impedance

NEET 2023

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

1Displacement current increases

2Displacement current decreases

3Capacitive reactance remains constant

4Capacitive reactance decreases

NTA Answer: Option 2(final)

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Lesson: Transformer

NEET 2023

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 to be ideal, what is the current in the primary winding?

12.7 A

23.7 A

30.37 A

40.27 A

NTA Answer: Option 4(final)

Report an error · Every fix is public: corrections log

Lesson: Self Inductance

NEET 2023

The magnetic energy stored in an inductor of inductance 4 µH carrying a current of 2 A is

14 mJ

28 mJ

38 µJ

44 µJ

NTA Answer: Option 3(final)

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Lesson: Resonance LCR

NEET 2023

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

115.9 kHz

21.59 rad/s

31.59 kHz

415.9 rad/s

NTA Answer: Option 3(final)

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Lesson: LCR Series Circuit

NEET 2023

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

115 Ω

25√5 Ω

325 Ω

410√2 Ω

NTA Answer: Option 2(final)

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Lesson: Peak RMS AC

NEET 2022

The peak voltage of the ac source is equal to

11/ 2 times the rms value of the ac source

2The value of voltage supplied to the circuit

3The rms value of the ac source

42 times the rms value of the ac source

NTA Answer: Option 4(final)

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Lesson: Faraday's Law

NEET 2022

A square loop of side 1 m and resistance 1 Ω is placed in a magnetic field of 0.5 T. If the plane of loop is perpendicular to the direction of magnetic field, the magnetic flux through the loop is

1Zero weber

22 weber

30.5 weber

41 weber

NTA Answer: Option 3(final)

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Lesson: Resonance LCR

NEET 2022

A series LCR circuit with inductance 10 H, capacitance 10 μF, resistance 50 Ω is connected to an ac source of voltage, V = 200sin(100t) volt. If the resonant frequency of the LCR circuit is ν₀ and the frequency of the ac source is ν, then

1ν = 100 Hz; ν₀ = 100/π Hz

2ν₀ = ν = 50 Hz

3ν₀ = ν = 50/π Hz

4ν₀ = 50/π Hz, ν = 50 Hz

NTA Answer: Option 3(final)

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NEET 2022

A big circular coil of 1000 turns and average radius 10 m is rotating about its horizontal diameter at 2 rad s⁻¹. If the vertical component of earth’s magnetic field at that place is 2 × 10⁻⁵ T and electrical resistance of the coil is 12.56 Ω, then the maximum induced current in the coil will be

12 A

20.25 A

31.5 A

41 A

NTA Answer: Option 4(final)

Report an error · Every fix is public: corrections log

Lesson: Transformer

NEET 2021

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 is the current in the primary circuit?

14 A

20.2 A

30.4 A

42 A

NTA Answer: Option 2(final)

Report an error · Every fix is public: corrections log

Lesson: Resonance LCR

NEET 2021

A series LCR circuit containing 5.0 H inductor, μF Ω 80 capacitor and 40 resistor is connected to 230 V variable frequency ac source. The angular frequencies of the source at which power transferred to the circuit is half the power at the resonant angular frequency are likely to be

142 rad/s and 58 rad/s

225 rad/s and 75 rad/s

350 rad/s and 25 rad/s

446 rad/s and 54 rad/s

NTA Answer: Option 4(final)

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Exam traps and common mistakes in this unit

Lesson: LCR Series Circuit

Trap

LCR resonance: negative-marking from cascading sub-formulas

Category: Negative Marking

Multi-step LCR resonance problem (compute resonance frequency, then current, then impedance). Each sub-step has factor-of-2π or sqrt-of-2 error opportunities. Final answer can be off by 4× cumulatively.

When it triggers

LCR question asks for current/voltage/power at resonance with multi-step computation.

How to avoid

Slow down. Compute f_0 = 1/(2π√(LC)) carefully. Then ω_0 = 2πf_0. Then Z = R, I = V/R. Each line one substitution; check unit/order at each step. Answers off by powers of 2π or √2 are deliberate distractors.

Lesson: Peak RMS AC

Mistake

Uses peak voltage where RMS expected (or vice versa).

Root cause: unit error

Correction

RMS = peak/√2 for sinusoidal AC. Stated AC voltages (e.g. 220 V mains) are RMS unless explicitly noted as peak. Power formulas use RMS.

Lesson: Resonance LCR

Mistake

Drops sqrt or 2π factor in resonance frequency formula.

Root cause: formula misuse

Correction

ω_0 = 1/√(LC); f_0 = 1/(2π√(LC)). Common errors: drop the sqrt (treat 1/(LC) as ω_0²), or drop the 2π (give ω_0 instead of f_0).

Lesson: Self Inductance

Mistake

Forgets squared on I in inductor energy formula.

Root cause: formula misuse

Correction

U = ½ L I² (analogous to capacitor's ½ C V² and KE's ½mv²). Common error: writes ½LI dropping the square.

Formulas in this unit

Lesson: Faraday's Law

Faraday's law of induction

ε = - \frac{d Φ _{B}}{d t}

Induced EMF in circuit equals negative rate of change of magnetic flux. Lenz's law in the sign.

Symbol	Quantity	SI Unit
epsilon	induced EMF	V
Phi_B	magnetic flux	Wb

Valid when

Closed loop
Flux change real (motion or B change)

Lesson: Induced EMF Current

Motional EMF

ε = B Lv

Rod of length L moving with v perpendicular to both rod and B; induced EMF from magnetic force on charges.

Symbol	Quantity	SI Unit
B	field	T
L	rod length	m
v	speed	m/s

Valid when

v ⊥ rod ⊥ B (all mutually perpendicular)
Uniform B

Lesson: LCR Series Circuit

LCR series impedance

Z = R^{2} + (X_{L} - X_{C})^{2}

Effective resistance of series LCR. Phase angle phi between V and I.

Symbol	Quantity	SI Unit
Z	impedance	Ω
R	resistance	Ω
X_L, X_C	reactances	Ω
phi	phase angle	rad

Valid when

Series LCR
AC steady state
Single frequency source

Lesson: Peak RMS AC

RMS values of sinusoidal AC

I_{rms} = \frac{I _{0}}{2}; V_{rms} = \frac{V _{0}}{2}

RMS values for pure sinusoid. Stated AC voltages are RMS unless noted.

Symbol	Quantity	SI Unit
I_rms	RMS current	A
I_peak	peak current	A
V_rms	RMS voltage	V
V_peak	peak voltage	V

Valid when

Pure sinusoid
Steady state

Lesson: Power in AC

Average AC power

P_{avg} = V_{rms} I_{rms} cos ϕ

Average power dissipated in AC circuit. cos(phi) = power factor.

Symbol	Quantity	SI Unit
P_avg	average power	W
V_rms, I_rms	RMS	V, A
phi	phase angle	rad

Valid when

Steady-state AC
Pure sinusoid

Lesson: Reactance Impedance

Capacitive reactance

X_{C} = \frac{1}{ω C}

Resistance-equivalent of capacitor in AC. Current leads voltage by 90°.

Symbol	Quantity	SI Unit
X_C	capacitive reactance	Ω
omega	angular freq	rad/s
C	capacitance	F

Valid when

Pure capacitor
AC steady state

Lesson: Reactance Impedance

Inductive reactance

X_{L} = ω L

Resistance-equivalent of inductor in AC circuit. Voltage leads current by 90°.

Symbol	Quantity	SI Unit
X_L	inductive reactance	Ω
omega	angular freq	rad/s
L	inductance	H

Valid when

Pure inductor
AC steady state

Lesson: Resonance LCR

Resonance frequency LCR

f_{0} = \frac{1}{2 π L C}

Frequency at which X_L = X_C, Z = R minimum, current maximum.

Symbol	Quantity	SI Unit
f0	resonance freq	Hz
L	inductance	H
C	capacitance	F

Valid when

Series LCR
Steady AC

Lesson: Self Inductance

Energy in inductor

U = \frac{1}{2} L I^{2}

Magnetic field energy stored in inductor carrying current I.

Symbol	Quantity	SI Unit
L	inductance	H
I	current	A

Valid when

Linear regime
Energy referenced to I=0

Lesson: Self Inductance

Self-inductance EMF

ε = - L \frac{d I}{d t}

EMF induced in coil due to its own changing current. L = inductance.

Symbol	Quantity	SI Unit
L	self inductance	H
I	current	A

Valid when

Coil/inductor
Linear regime (no core saturation)

Lesson: Transformer

Transformer ratios

\frac{V _{s}}{V _{p}} = \frac{N _{s}}{N _{p}}

Voltage ratio = turns ratio. Ideal transformer: V_p I_p = V_s I_s.

Symbol	Quantity	SI Unit
V_p, V_s	primary, secondary V	V
N_p, N_s	turns	-
I_p, I_s	currents	A

Valid when

Ideal transformer (no losses)
Common iron core

NEET question patterns in this unit

Lesson: Faraday's Law

EMF induced in coil by changing flux. Lenz's law sign: opposes change.

InterpretationMedium

Common distractors

wrong sign direction

Picks induced current in wrong direction

Lesson: LCR Series Circuit

Series LCR resonance frequency f0 = 1/(2π sqrt(LC)). At resonance Z=R, current max.

Multi StepMedium

Common distractors

forgets square root

Uses 1/(2π LC) without sqrt

conflates X_L X_C formulas

Substitutes wrong reactance formula

Lesson: Peak RMS AC

Convert between peak and RMS for sinusoidal AC: factor sqrt(2).

Direct ApplicationEasy

Common distractors

forgets sqrt 2

Treats peak = RMS

Lesson: Reactance Impedance

Compute X_L = ωL or X_C = 1/(ωC) at given frequency. Compare phase relationships.

Direct ApplicationEasy

Common distractors

swaps XL XC formulas

Uses XL formula for capacitor

Lesson: Self Inductance

Energy stored in inductor: U = ½ L I^2.

Direct ApplicationEasy

Common distractors

uses LI not LI squared

Drops square on I

forgets 1 2 factor

Uses LI^2 without 1/2

Lesson: Transformer

Transformer: V_s/V_p = N_s/N_p. Step-up vs step-down. Ideal: V_p I_p = V_s I_s.

Direct ApplicationEasy

Common distractors

inverts ratio direction

Confuses step-up vs step-down assignment

Questions about this unit

What does Electromagnetic Induction and Alternating Currents cover for NEET Physics?: 14 lessons: Alternating Currents, Eddy Currents, Faraday's Law, Induced EMF Current, LCR Series Circuit, Lenz's Law, Mutual Inductance, Peak RMS AC, Power in AC, Reactance Impedance, Resonance LCR, Self Inductance, Transformer and Wattless Current.
How often has Electromagnetic Induction and Alternating Currents come up in NEET past papers?: Our set of verified past papers has 20 questions from this unit, from NEET 2021, 2022, 2023, 2024, 2025 and 2026. Each is answered against the official NTA key.
Is the Electromagnetic Induction and Alternating Currents material free?: Yes. All 14 lessons and 112 practice questions are free, with no login needed.

Electromagnetic Induction and Alternating Currents

Topic index in NCERT order

Class 12 Physics, Chapter 6

Class 12 Physics, Chapter 7

Class 12 Physics (pre-2023 edition), Chapter 6

Alternating Currents

Eddy Currents

Faraday's Law

Induced EMF Current

LCR Series Circuit

Lenz's Law

Mutual Inductance

Peak RMS AC

Power in AC

Reactance Impedance

Resonance LCR

Self Inductance

Transformer

Wattless Current

Past-paper questions from this unit

Exam traps and common mistakes in this unit

When it triggers

How to avoid

Correction

Correction

Correction

Formulas in this unit

Valid when

Valid when

Valid when

Valid when

Valid when

Valid when

Valid when

Valid when

Valid when

Valid when

Valid when

NEET question patterns in this unit

Common distractors

Common distractors

Common distractors

Common distractors

Common distractors

Common distractors

Questions about this unit