Electromagnetic Fields and Waves MCQs (Part-8)

What is the purpose of a waveguide in an electromagnetic system?

A Amplify signals
B Reflect signals
C Transmit signals
D Absorb signals

Which type of electromagnetic wave is primarily used in radar systems?

A Microwaves
B Radio waves
C X-rays
D Gamma rays

What does electromagnetic interference (EMI) typically cause in electronic circuits?

A Signal enhancement
B Increased frequency
C Reduced current
D Signal distortion

What is the effect of a dielectric material between the plates of a capacitor?

A Decreases capacitance
B Increases capacitance
C Increases resistance
D Decreases resistance

What happens when an electromagnetic wave moves from a low–density medium to a high–density medium?

A Wave is absorbed
B Speed increases
C Speed decreases
D No change in speed

What does a low–pass filter allow in an electromagnetic system?

A High–frequency signals
B All signals
C Only noise
D Low–frequency signals

What is the basic principle behind electromagnetic wave transmission?

A Electric and magnetic field interaction
B Magnetic induction
C Waveguiding
D Electric field variation

Which of the following affects the propagation speed of electromagnetic waves in a material?

A Electric conductivity
B Magnetic permeability
C Both B and C
D Electric permittivity

What type of waves are used for communication in optical fibers?

A Radio waves
B Light waves
C Microwaves
D X–rays

What is the primary function of shielding in electromagnetic systems?

A Block unwanted signals
B Increase signal strength
C Absorb radiation
D Reflect radiation

What does a waveguide typically consist of?

A A dielectric material
B A conductor and insulator
C A hollow metallic tube
D A solid dielectric core

What happens when an electromagnetic wave passes through a medium with a lower refractive index?

A Speed decreases
B No change in speed
C Wave disappears
D Speed increases

Which of the following is a common source of electromagnetic interference (EMI)?

A Motors
B Batteries
C Diodes
D Capacitors

What happens when an electromagnetic wave is incident at the critical angle on a boundary between two media?

A Refraction
B Diffraction
C Total reflection
D Polarization

How does an increase in frequency affect the wavelength of an electromagnetic wave in a given medium?

A Increases wavelength
B Decreases wavelength
C No change
D Increases amplitude