Electromagnetic Fields and Waves MCQs (Part-12)

What is the unit of magnetic flux?

A Tesla (T)
B Ampere-Turns per meter (A/m)
C Weber (Wb)
D Volt per meter (V/m)

What is the fundamental property of a magnetic dipole?

A It has a positive charge
B It has both positive and negative charges separated by a distance
C It consists of two opposite magnetic poles separated by a distance
D It generates a uniform electric field

What is inductance a measure of?

A The ability of a conductor to resist current
B The ability of a material to store electric charge
C The ability of a conductor to oppose changes in current
D The ability of a material to support the formation of an electric field

What does the term “magnetostatics” refer to?

A The study of electric fields in static conditions
B The study of magnetic fields in steady (static) conditions
C The study of time-varying magnetic fields
D The interaction of magnetic and electric fields

What is the relationship between magnetic field intensity (H) and magnetic flux density (B)?

A \( B = \mu_0 H \)
B \( B = \mu_0 \varepsilon_0 H \)
C \( B = \mu H \)
D \( B = H \varepsilon_0 \)

What does the term “permittivity” (\( \varepsilon \)) refer to in electromagnetics?

A The ability of a material to oppose changes in electric field
B The ability of a material to support the formation of an electric field
C The ability of a material to conduct electric current
D The ability of a material to store magnetic energy

What happens when an electromagnetic wave passes through a dielectric material?

A The wave is completely absorbed by the material
B The wave speed increases
C The wave slows down, and the wavelength decreases
D The wave is reflected back entirely

What is the primary purpose of a resonant cavity in microwave devices?

A To store electrical energy
B To support standing waves at specific resonant frequencies
C To increase the speed of electromagnetic waves
D To filter signals based on frequency

What is the unit of inductance?

A Farad (F)
B Henry (H)
C Ohm (Ω)
D Volt (V)

What is the effect of an external magnetic field on an electric dipole?

A It causes the dipole to align with the magnetic field
B It causes the dipole to change its charge distribution
C It induces a net electric charge in the dipole
D It causes the dipole to move and orient itself in the direction of the field

What is the effect of increasing permeability in a magnetic material on magnetic fields?

A It increases the resistance of the magnetic field
B It decreases the magnetic field strength
C It increases the ability of the material to conduct magnetic flux
D It reduces the ability to conduct magnetic flux

What is the primary purpose of a magnetic circuit?

A To store electric charge
B To control the flow of magnetic flux
C To generate electric fields
D To store energy in the form of magnetic fields

What is the role of a dielectric material in an electromagnetic wave system?

A To amplify the wave’s strength
B To store energy in the form of an electric field
C To reflect the wave
D To reduce the wave’s frequency

What is the primary cause of electromagnetic radiation in antennas?

A The reflection of waves from the antenna surface
B The oscillation of the electric and magnetic fields
C The absorption of electromagnetic waves by the antenna
D The movement of electrons within the antenna structure

What is the effect of increasing the frequency of an electromagnetic wave on its energy?

A The energy decreases
B The energy increases
C The energy remains constant
D The energy becomes zero

What is the primary effect of the skin effect in high-frequency current conduction?

A The current tends to flow near the surface of the conductor at higher frequencies
B The current flows uniformly throughout the conductor
C The current decreases at the surface of the conductor
D The current becomes constant inside the conductor

What is the primary function of a resonant cavity in microwave devices?

A To store electromagnetic energy at specific frequencies
B To increase the frequency of electromagnetic waves
C To convert electromagnetic waves into electric power
D To filter out unwanted electromagnetic waves

What is the role of eddy currents in electromagnetic systems?

A To enhance electromagnetic wave transmission
B To generate heat in conductors
C To create magnetic fields in materials
D To store energy in the form of magnetic fields

What is the primary cause of electromagnetic radiation in antennas?

A The movement of electrons within the antenna structure
B The oscillation of the electric and magnetic fields
C The reflection of waves from the antenna surface
D The absorption of electromagnetic waves by the antenna

What is the primary effect of an increase in permeability on a magnetic circuit?

A It increases the resistance of the magnetic circuit
B It increases the intensity of the magnetic field
C It reduces the amount of magnetic flux
D It reduces the intensity of the magnetic field