Electromagnetic Fields and Waves MCQs (Part-6)

What does Gauss’s Law describe in terms of electric fields?

A The relationship between electric fields and currents
B The relationship between electric fields and charge distributions
C The relationship between electric fields and magnetic fields
D The relationship between electric fields and voltage

Which of the following is a key feature of Faraday’s Law of Induction?

A It relates magnetic fields to electric currents
B It relates electric fields to time-varying magnetic fields
C It explains how electric fields are generated by static charges
D It explains the behavior of electric fields in conductors

What is the principle behind Ampere’s Law?

A The electric field is proportional to the charge enclosed
B The magnetic field is proportional to the current enclosed by a loop
C The magnetic field is proportional to the electric field
D The electric potential is constant around a closed loop

What is the displacement current?

A The current in a conductor caused by a time-varying electric field
B The total current flowing in a circuit
C The current due to the motion of free charges
D The induced current in a conductor due to a changing magnetic field

In the context of boundary conditions for electromagnetic fields, what does “continuity of the tangential component of the electric field” refer to?

A The electric field does not change when crossing a boundary
B The tangential component of the electric field remains constant across a boundary
C The tangential component of the electric field must be zero at a boundary
D The electric field can only exist in vacuum

What is the phenomenon of polarization in electromagnetic waves?

A The bending of light when it passes through a boundary
B The alignment of the electric field vector in a specific direction
C The splitting of light into different components
D The absorption of electromagnetic waves by materials

What happens during the reflection of electromagnetic waves at a boundary?

A The wave bends when passing into a new medium
B The wave bounces back, possibly with a change in direction or phase
C The wave is absorbed by the surface
D The wave passes through the surface without any change

What does the term “refraction” describe in wave propagation?

A The bending of waves around obstacles
B The change in direction of waves when they pass from one medium to another
C The reflection of waves from a surface
D The spreading of waves when they pass through an opening

What is diffraction in wave theory?

A The bending of waves around obstacles or through small openings
B The splitting of waves into multiple components
C The reflection of waves at a boundary
D The absorption of waves by a material

What is the wave equation for a non-dispersive electromagnetic wave?

A \( E(x,t) = E_0 \sin(kx – \omega t) \)
B \( \nabla^2 E = \mu \epsilon \frac{\partial^2 E}{\partial t^2} \)
C \( E(x,t) = E_0 \exp(-kx + \omega t) \)
D \( \nabla^2 E = 0 \)

What is the primary function of antennas in electromagnetic communication systems?

A To convert electrical signals into mechanical motion
B To convert electrical signals into electromagnetic waves for transmission
C To store electromagnetic waves
D To amplify electromagnetic signals

What is the primary role of a waveguide?

A To store electromagnetic energy
B To propagate electromagnetic waves in a specific direction with minimal loss
C To convert electromagnetic energy into sound
D To increase the amplitude of electromagnetic waves

Which part of the electromagnetic spectrum has the shortest wavelength?

A Radio waves
B Microwaves
C Visible light
D Gamma rays

What does the polarization of light refer to?

A The change in frequency of light as it passes through a medium
B The orientation of the electric field oscillation in the wave
C The reflection of light from a surface
D The bending of light when passing through a medium

Which of the following is true about electromagnetic wave propagation in a vacuum?

A Electromagnetic waves require a medium to travel
B Electromagnetic waves travel at the speed of light in a vacuum
C Electromagnetic waves cannot travel through a vacuum
D Electromagnetic waves travel faster than the speed of light in a vacuum

What is the main difference between a conductor and a dielectric material in the context of electric fields?

A Dielectrics support electric fields, while conductors block them
B Conductors allow electric current to flow, while dielectrics do not
C Dielectrics have no electric field, while conductors always do
D Conductors support electric fields, while dielectrics do not

What is the role of permittivity in an electromagnetic wave?

A It measures the ability of a material to store magnetic energy
B It measures the ability of a material to support the formation of an electric field
C It controls the speed of light in a material
D It affects the polarization of the material

What is the role of permittivity in an electromagnetic wave?

A It measures the ability of a material to store magnetic energy
B It measures the ability of a material to support the formation of an electric field
C It controls the speed of light in a material
D It affects the polarization of the material

What is the boundary condition for the normal component of the magnetic field at a boundary between two materials?

A It may have a discontinuity depending on the material
B It must be continuous across the boundary
C It must be zero across the boundary
D It must match the tangential electric field

What is the skin effect in alternating current (AC) conduction?

A The phenomenon where AC current tends to flow near the surface of a conductor
B The increase of current at deeper layers of a conductor
C The reduction of current at the surface of a conductor
D The equal distribution of current throughout a conductor

What is the main function of an antenna in an electromagnetic wave system?

A To amplify signals
B To convert electrical signals into electromagnetic waves for transmission
C To store electromagnetic waves
D To direct electromagnetic waves