Electromagnetic Waves – JEE Physics Questions with Solutions

Q1. AI-generated practice Single-correct MCQ Easy

The displacement current introduced by Maxwell is given by:

Adq/dt × μ₀
Bε₀Φ_E
Cε₀ dΦ_E/dt
Dμ₀ dΦ_B/dt

Q2. AI-generated practice Single-correct MCQ Easy

Maxwell introduced the idea of displacement current mainly to:

A
explain the heating effect of current
B
explain why currents attract each other
C
make Ampere's circuital law consistent for a charging capacitor
D
explain the photoelectric effect

Q3. AI-generated practice Single-correct MCQ Medium

A capacitor is being charged by a current of 2 A in the connecting wires. The displacement current between its plates is:

A
2 A
B
1 A
C
zero
D
4 A

Q4. AI-generated practice Single-correct MCQ Medium

The electric field between the plates of a parallel-plate capacitor of plate area 0.01 m² changes at a rate of 10¹² V m^-1 s^-1. Take ε₀ = 8.85 × 10^-12 C² N^-1 m^-2. The displacement current is about:

A
0.089 A
B8.9 × 10^-14 A
C
0.89 A
D
8.9 A

Q5. AI-generated practice Single-correct MCQ Medium

The Ampere–Maxwell law states that ∮B · dl is equal to:

A
zero
Bμ₀I
C−dΦ_B/dt
Dμ₀(I + ε₀ dΦ_E/dt)

Q6. AI-generated practice Single-correct MCQ Hard

A capacitor with circular plates of radius R is being charged by a current I. The magnetic field between the plates at a distance r (smaller than R) from the axis is:

A
zero
Bμ₀Ir/(2πR²)
Cμ₀I/(2πR)
Dμ₀I/(2πr)

Q7. AI-generated practice Single-correct MCQ Medium

Which of Maxwell's equations expresses the fact that isolated magnetic poles do not exist?

A∮E · dA = q/ε₀
B
∮B · dA = 0
C∮B · dl = μ₀(I + ε₀ dΦ_E/dt)
D∮E · dl = −dΦ_B/dt

Q8. AI-generated practice Single-correct MCQ Easy

A displacement current exists:

A
only when charges move through a wire
B
only inside metallic conductors
C
only in steady DC circuits
D
wherever the electric flux changes with time, even in vacuum

Q9. AI-generated practice Single-correct MCQ Hard

The potential difference across a 2 μF capacitor is changing at a rate of 5 × 10⁵ V/s. The displacement current between its plates is:

A
1 A
B
2.5 A
C
10 A
D
0.1 A

Q10. AI-generated practice Single-correct MCQ Medium

Maxwell's equations predict that electromagnetic waves travel in vacuum with a speed equal to:

Aμ₀/ε₀
B1/√(μ₀ε₀)
C√(μ₀ε₀)
D1/(μ₀ε₀)

Q11. AI-generated practice Single-correct MCQ Medium

Displacement current differs from conduction current in that it:

A
does not involve the motion of charges
B
cannot produce a magnetic field
C
is always larger than the conduction current
D
flows only in conductors

Q12. AI-generated practice Single-correct MCQ Hard

A capacitor has circular plates of radius 5 cm and is being charged by a current of 1 A. The magnetic field at the edge of the plates (r = 5 cm from the axis, between the plates) is (μ₀/4π = 10^-7 T m/A):

A8 × 10^-6 T
B
zero
C4 × 10^-6 T
D2 × 10^-6 T

Q13. AI-generated practice Single-correct MCQ Easy

Electromagnetic waves were first produced and detected experimentally by:

A
Michael Faraday
B
Guglielmo Marconi
C
James Clerk Maxwell
D
Heinrich Hertz

Q14. AI-generated practice Single-correct MCQ Medium

The quantity ε₀ dΦ_E/dt has the same SI unit as:

A
electric charge
B
electric current
C
magnetic flux
D
electric field

Q15. AI-generated practice Numerical value Easy

A capacitor is being charged by a steady current of 3 A in the connecting wires. Find the displacement current (in ampere) between its plates.

Q16. AI-generated practice Numerical value Medium

The voltage across a 1 μF capacitor increases at a rate of 2 × 10⁶ V/s. Find the displacement current (in ampere) between its plates.

Q17. AI-generated practice Numerical value Medium

The electric flux through a surface changes at a rate of 5.65 × 10¹¹ V m s^-1. Take ε₀ = 8.85 × 10^-12 C² N^-1 m^-2. Find the displacement current through the surface in ampere, to the nearest integer.

Q18. AI-generated practice Numerical value Hard

A capacitor with circular plates of radius 10 cm is being charged by a current of 6 A. If the magnetic field between the plates at 5 cm from the axis is x × 10^-6 T, find x. (μ₀/4π = 10^-7 T m/A)

Q19. AI-generated practice Assertion–Reason Medium

Assertion (A): A magnetic field exists in the region between the plates of a capacitor while it is being charged.
Reason (R): The changing electric field between the plates gives rise to a displacement current.

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): Displacement current flows only inside conductors.
Reason (R): Displacement current is proportional to the rate of change of electric flux.

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