Question 1

Which of the following statements best describes Maxwell’s unification of electric and magnetic phenomena?

Accepted Answer

He unified electric and magnetic phenomena using four equations, showing that changing electric fields produce magnetic fields and vice versa.

Question 2

Which of Maxwell’s equations states that a changing magnetic field produces an electric field?

Accepted Answer

Faraday’s Law

Question 3

What is the physical significance of the displacement current introduced by Maxwell?

Accepted Answer

It accounts for the magnetic field produced by a changing electric field, even when no charge physically moves.

Question 4

Consider a parallel-plate capacitor being charged. According to Maxwell’s correction to Ampère’s Law, what produces the magnetic field between the plates?

Accepted Answer

The displacement current due to the changing electric field.

Question 5

A charge oscillates back and forth in empty space. What is the result of this oscillation?

Accepted Answer

Electromagnetic waves are produced, propagating away from the charge.

Question 6

Which of the following correctly describes the orientation of the electric field ($$\vec{E}$$), magnetic field ($$\vec{B}$$), and direction of propagation for an electromagnetic wave?

Accepted Answer

$$\vec{E}$$ and $$\vec{B}$$ are perpendicular to each other and both are perpendicular to the direction of propagation.

Question 7

Maxwell derived the speed of electromagnetic waves in vacuum as $$c = \frac{1}{\sqrt{\mu_0$ \$$epsilon_0$$}}. $$What does this result imply?

Accepted Answer

Light is an electromagnetic wave whose speed is determined by the permittivity and permeability of free space.

Question 8

Which of the following best describes the effect of distance on the intensity of electromagnetic waves from a point source?

Accepted Answer

Intensity decreases as the inverse square of the distance from the source.

Question 9

A solar sail is propelled by sunlight in space. Which physical property of electromagnetic waves is responsible for this propulsion?

Accepted Answer

The radiation pressure exerted by the momentum of absorbed or reflected light.

Question 10

Unpolarized light of intensity $$I_0$$ passes through a polarizer. What is the intensity of the transmitted light?

Accepted Answer

$$\frac{I_0$}{2}$$

Question 11

If two ideal polarizers are placed perpendicular to each other, what is the intensity of light transmitted through both if the incident light is unpolarized?

Accepted Answer

$$0$$

Question 12

Malus’ Law gives the intensity of light after passing through a polarizer at angle $$	heta to $$the initial polarization direction as $$I = I_0$ \cos^2$ 	heta. If$$ $$I_0 = 100$ W/m^2$ and $$	heta = 60^\circ$$, what is the transmitted intensity?

Accepted Answer

$$I = 25 W/m$^2$$

Question 13

Which of the following is NOT a consequence of Maxwell’s equations?

Accepted Answer

Magnetic monopoles exist in nature.

Question 14

A radio antenna emits electromagnetic waves. What is the primary mechanism by which these waves are generated?

Accepted Answer

Oscillating charges in the antenna produce changing electric and magnetic fields, which propagate as electromagnetic waves.

Question 15

Which equation relates the energy density $$u of an $$electromagnetic wave to the electric field $$E$$ and magnetic field $$B$$?

Accepted Answer

$$u = \frac{1}{2} \$$epsilon_0$$ E^2$ + \frac{1}{2} \frac{B^2$}{\mu_0$}$$

Question 16

A beam of light is reflected from a perfectly reflecting surface. How does the momentum transferred to the surface compare to that from an absorbing surface?

Accepted Answer

It is twice as much.

Question 17

Which region of the electromagnetic spectrum has the shortest wavelength?

Accepted Answer

Gamma rays

Question 18

If the frequency of an electromagnetic wave is doubled while its speed remains constant, what happens to its wavelength?

Accepted Answer

It is halved.

Question 19

Which of the following best describes linear polarization of light?

Accepted Answer

The electric field oscillates in a single plane perpendicular to the direction of propagation.

Electromagnetic Waves and Polarization: Maxwell’s Equations and Applications

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