Electromagnetic Induction and Alternating Currents – JEE Physics Questions with Solutions

Q1. AI-generated practice Single-correct MCQ Easy

A flat coil of area 0.02 m² is in a uniform magnetic field of 0.5 T. The normal to the coil makes an angle of 60° with the field. The magnetic flux through one turn is:

A8.7 × 10^-3 Wb
B5 × 10^-3 Wb
C1 × 10^-2 Wb
D2.5 × 10^-3 Wb

Q2. AI-generated practice Single-correct MCQ Easy

The SI unit of magnetic flux is the weber, which is equal to:

AT/m²
BA m²
C
T m
DT m²

Q3. AI-generated practice Single-correct MCQ Medium

A coil of 100 turns has the flux through each turn reduced from 0.02 Wb to 0.005 Wb in 0.1 s. The average induced emf is:

A
1.5 V
B
25 V
C
15 V
D
0.15 V

Q4. AI-generated practice Single-correct MCQ Medium

The magnetic flux through a single loop varies with time as Φ = (5t² + 3t) mWb, with t in seconds. The magnitude of the induced emf at t = 2 s is:

A
23 mV
B
26 mV
C
13 mV
D
20 mV

Q5. AI-generated practice Single-correct MCQ Medium

A single loop of area A is held with its normal along a uniform field B. It is then turned through 180° about a diameter. The magnitude of the change in flux through it is:

A
zero
B
BA
C
2BA
D
BA/2

Q6. AI-generated practice Single-correct MCQ Hard

A coil of 50 turns and resistance 10 Ω is connected to a galvanometer of negligible resistance. The flux through each turn changes by 4 × 10^-3 Wb. The charge that flows through the circuit is:

A2 × 10^-3 C
B
0.2 C
C
0.02 C
D
it depends on how fast the flux changes

Q7. AI-generated practice Single-correct MCQ Medium

A rectangular wire loop moves with constant velocity entirely inside a region of uniform magnetic field, keeping its orientation. The induced emf in the loop is:

A
zero
B
Bv/l
C
2Bvl
D
Bvl

Q8. AI-generated practice Single-correct MCQ Hard

A loop of area 0.01 m² is placed perpendicular to a magnetic field B = 0.2 sin(100t) T. The amplitude of the induced emf is:

A
0.2 V
B
2 V
C
0.02 V
D
0.002 V

Q9. AI-generated practice Single-correct MCQ Easy

Faraday's law of electromagnetic induction states that the induced emf in a circuit is equal to:

A
the magnetic flux through the circuit
B
the rate of change of current in the circuit
C
the product of flux and time
D
the negative of the rate of change of magnetic flux through the circuit

Q10. AI-generated practice Single-correct MCQ Medium

A circular loop of radius 10 cm lies perpendicular to a magnetic field that increases at a steady rate of 0.5 T/s. The induced emf in the loop is about:

A
5 mV
B
15.7 mV
C
31.4 mV
D
1.57 mV

Q11. AI-generated practice Single-correct MCQ Hard

A flexible circular loop in a uniform field of 0.4 T (perpendicular to its plane) is shrinking so that its radius decreases at 1 cm/s. The emf induced in it when the radius is 5 cm is about:

A
0.63 mV
B
12.6 mV
C
3.1 mV
D
1.26 mV

Q12. AI-generated practice Single-correct MCQ Medium

The magnetic flux through a coil increases linearly with time. The induced emf in the coil:

A
is zero
B
is constant
C
increases linearly with time
D
decreases linearly with time

Q13. AI-generated practice Single-correct MCQ Easy

When a bar magnet is pushed into a coil connected to a galvanometer, the deflection is larger if the magnet is moved:

A
with its north pole first
B
faster
C
with its south pole first
D
slower

Q14. AI-generated practice Single-correct MCQ Hard

A coil of 200 turns, each of area 5 × 10^-3 m², is placed perpendicular to a magnetic field of 0.6 T. The field is reduced uniformly to zero in 0.05 s. The average induced emf is:

A
12 V
B
24 V
C
0.06 V
D
6 V

Q15. AI-generated practice Numerical value Easy

The magnetic flux through a single loop changes by 0.4 Wb in 0.2 s. Find the average induced emf in volt.

Q16. AI-generated practice Numerical value Medium

A coil of 500 turns, each of area 4 × 10^-3 m², is placed perpendicular to a magnetic field that rises uniformly from 0 to 0.2 T in 0.1 s. Find the average induced emf in volt.

Q17. AI-generated practice Numerical value Medium

A coil of 100 turns and total resistance 5 Ω has the flux through each turn changed by 2 × 10^-3 Wb. Find the charge (in mC) that flows through the coil.

Q18. AI-generated practice Numerical value Hard

The flux through a single loop varies as Φ = (2t³ − 3t²) mWb, with t in seconds. Find the magnitude of the induced emf (in mV) at t = 2 s.

Q19. AI-generated practice Assertion–Reason Medium

Assertion (A): An emf is induced in a closed loop whenever the magnetic flux through it changes.
Reason (R): The induced emf equals the negative of the rate of change of magnetic flux through the loop.

A
Both A and R are true and R is the correct explanation of A
B
Both A and R are true but R is not the correct explanation of A
C
A is true but R is false
D
A is false but R is true

Q20. AI-generated practice Assertion–Reason Hard

Assertion (A): The total charge that flows through a coil because of a change of flux depends on how quickly the flux changes.
Reason (R): The induced emf is larger when the flux changes faster.

A
Both A and R are true and R is the correct explanation of A
B
Both A and R are true but R is not the correct explanation of A
C
A is true but R is false
D
A is false but R is true