NEET (UG)

Practice Test 1 — Electromagnetic Waves

12 questions • 18 minutes • auto-graded with full solutions

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Section A — MCQ (Single Correct)

Question 1

The displacement current is given by:

Solution: $I_d = \varepsilon_0\,d\Phi_E/dt$.

Question 2

Electromagnetic waves are:

Solution: EM waves are transverse.

Question 3

The speed of light in vacuum is:

Solution: $c = 1/\sqrt{\mu_0\varepsilon_0}$.

Question 4

In an EM wave, the ratio $E_0/B_0$ equals:

Solution: $E_0/B_0 = c$.

Question 5

Which has the shortest wavelength?

Solution: Gamma rays have the shortest wavelength.

Question 6

Visible light wavelength range is roughly:

Solution: About $400$–$700\ \text{nm}$.

Question 7

Radar and satellite communication use:

Solution: Microwaves are used in radar and satellite links.

Question 8

The photon energy of an EM wave is:

Solution: $E = hf$.

Section B — Assertion & Reason

Question 9

A: A magnetic field exists between the plates of a charging capacitor even though no charge crosses the gap.
R: The changing electric field there constitutes a displacement current that produces a magnetic field.

Solution: Displacement current from the changing $E$ field produces the magnetic field — R explains A.

Question 10

A: Electromagnetic waves can travel through vacuum.
R: EM waves are produced by oscillating electric and magnetic fields that sustain each other and need no material medium.

Solution: Self-sustaining fields need no medium, so they cross vacuum — R explains A.

Question 11

A: Gamma rays have a longer wavelength than radio waves.
R: Wavelength decreases as frequency increases for electromagnetic waves.

Solution: Gamma rays have a much shorter wavelength than radio waves, so A is false; R correctly states $\lambda$ falls as $f$ rises.

Question 12

A: Electromagnetic waves can exert pressure on a surface.
R: EM waves carry momentum as well as energy.

Solution: Carrying momentum is exactly why they exert radiation pressure — R explains A.