Electromagnetic Interview Questions

Electromagnetic Interview Questions

  • Anuj Awasthi
  • 17th Apr, 2021

Electromagnetic Interview Questions

1) What do you mean by electromagnetic?

Electromagnetic is used to describe the electrical and magnetic forces or effects produced by an electric current.It comes under the branch of Electromagnetism that involves the study of the electromagnetic force. It is a type of interaction that occurs between electrically charged particles.

2) What makes Electromagnetic radiation?

Electromagnetic radiation is made when an atom absorbs energy. The absorbed energy causes one or more electrons to change their locale within the atom. When the electron returns to its original position, an electromagnetic wave is produced.

3) What is an electromagnet object?

An electromagnet object is a type of magnet in which the magnetic field is produced by an electric current. Electromagnets usually consist of wire wound into a coil. A current through the wire creates a magnetic field which is concentrated in the hole, denoting the center of the coil.

4) How an electromagnetic field is generated?

An electromagnetic field, sometimes referred to as an EM field, is generated when charged particles, such as electrons, are accelerated. Charged particles in motion produce magnetic fields. When the velocity of a charged particle changes, an EM field is produced.

5) What is electromagnetic induction?

Electromagnetic or magnetic induction is the production of an electromotive force (i.e., voltage) across an electrical conductor in a changing magnetic field.

6) What do you know about Rayleigh scattering?

Rayleigh scattering is the scattering of light by particles in a medium, without a change in wavelength. It was named after the nineteenth-century British physicist Lord Rayleigh, is the predominantly elastic scattering of light or other electromagnetic radiation by particles much smaller than the wavelength of the radiation.

7) What is IP3 value of an amplifier?

The IP3 value is an imaginary point that indicates when the amplitude of the third-order products equals the input signals. This point is never reached, as the amplifier will saturate before this condition can occur.

8) What are degenerative modes?

Degenerate modes are the special case when two modes (maybe more?) have the same propagation constant. This is significant because the modes will stay synchronized as they propagate making it very easy to couple power from one mode to the other.

9) List some advantages of using optical fibres?

Few advantages of optical fiber are

  • Higher bandwidth support.
  • High carrying capacity.
  • Immunity to electromagnetic interference and tapping.
  • Optical fiber are so flexible.
  • Optical fiber cables take up less space.
  • Less signal attenuation.
  • Resistance to corrosive materials.

10) What are Superparamagnetism?

Superparamagnetism is the magnetic behavior associated with magnetic nanoparticles, generally of ferromagnetic or ferrimagnetic materials, corresponding to a single magnetic domain and a high magnetic moment.

11) What is drift velocity?

Drift velocity is the average velocity attained by charged particles, such as electrons, in a material due to an electric field. In general, an electron in a conductor will propagate randomly at the Fermi velocity, resulting in an average velocity of zero.

12) Explain Fleming's right hand rule?

Fleming's right-hand rule gives which direction the current flows. The right hand is held with the thumb, index finger and middle finger mutually perpendicular to each other (at right angles), as shown in the diagram. The thumb is pointed in the direction of the motion of the conductor relative to the magnetic field.

13) What is magnetic flux?

Magnetic flux is a measurement of the total magnetic field which passes through a given area. It is a useful tool for helping describe the effects of the magnetic force on something occupying a given area. The measurement of magnetic flux is tied to the particular area chosen. We can choose to make the area any size we want and orient it in any way relative to the magnetic field.

14) List some applications of electromagnetism.

Some applications of electromagnetism are

  • Generators, motors, and transformers.
  • Electric buzzers and bells.
  • Headphones and loudspeakers.
  • Relays and valves.
  • Data storage devices like VCRs, tape recorders, hard discs, etc.
  • Induction cooker.
  • Magnetic locks.
  • MRI machines.

15) What is a commutator?

A commutator is a rotary electrical switch in certain types of electric motors and electrical generators that periodically reverses the current direction between the rotor and the external circuit. It consists of a cylinder composed of multiple metal contact segments on the rotating armature of the machine.

16) What is phenomenon of Electromagnetic Induction?

Electromagnetic induction is a phenomenon in which a changing magnetic field across a loop of wire results in the generation of an induced emf. When there is relative motion between a magnet and the coil, magnetic flux changes and hence an electromotive force is generated in the coil.

17) What are Air core coils?

Air core coils is an inductor that does not depend upon a ferromagnetic material to achieve its specified inductance. They have coils wound on plastic, ceramic, and other non-magnetic cores like those filled with air.

18) What are the four Maxwell's equations?

The four Maxwell's Equations are

  • Gauss's law: Electric charges produce an electric field. The electric flux across a closed surface is proportional to the charge enclosed.
  • Gauss's law for magnetism: There are no magnetic monopoles. The magnetic flux across a closed surface is zero.
  • Faraday's law: Time-varying magnetic fields produce an electric field.
  • Ampère's law: Steady currents and time-varying electric fields (the latter due to Maxwell's correction) produce a magnetic field.

19) What are Conductors and Insulators?

Conductor: An electrical conductor is a substance in which electrical charge carriers, usually electrons, move easily from atom to atom with the application of voltage.

Insulator: Insulators are materials that inhibit the flow of electrical current. The opposite of conductors, which allow electric particles to flow freely, insulators are implemented in household items and electrical circuits as protection. Thermal insulation is similar, but it constricts the flow of heat rather than electricity.

20) What are Irrotational and Solenoidal Vector Fields?

Irrotational vector field: An irrotational vector field is a vector field where curl is equal to zero everywhere. If the domain is simply connected (there are no discontinuities), the vector field will be conservative or equal to the gradient of a function (that is, it will have a scalar potential).

Solenoidal vector field: In vector calculus, a solenoidal vector field (also known as an incompressible vector field, a divergence-free vector field, or a transverse vector field) is a vector field v with divergence zero at all points in the field: A common way of expressing this property is to say that the field has no sources or sinks.

21) Explain Harmonic Wave?

A harmonic Wave is a signal or wave whose frequency is an integral (whole number) multiple of the frequency of some reference signal or wave. The term can also refer to the ratio of the frequency of such a signal or wave to the frequency of the reference signal or wave.

22) What is Electric Polarization?

Electric polarization refers to the separation of the center of positive charge and the center of negative charge in a material. The separation can be caused by a sufficiently high electric field. The polarization induces an increase of the measured electrical resistivity of carbon fiber–reinforced cement paste during resistivity measurement.

23) What are Multielectron Atoms?

Atoms with more than one electron, such as Helium (He) and Nitrogen (N), are referred to as multielectron atoms.

24) What is Ultraviolet light?

Ultraviolet light is a type of electromagnetic radiation that makes black-light posters glow, and is responsible for summer tans — and sunburns. However, too much exposure to UV radiation is damaging to living tissue.

25) What is wavelength?

The distance between successive crests of a wave, especially points in a sound wave or electromagnetic wave is called Wavelength.

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