EMI and EMC multiple choice questions

 EMI and EMC

1. The unit of electrical field intensity is _________. Where , V is volt and m is meter.
a) V/m
b) V . m
c) m / V
d)V2/m
Answer: V/m
2. ______________ high-frequency EMI source.
a) radio
b) television
c) marine communication
d) all of these
Answer: all of these
3. Any conductor carrying elect ri cal current has an associated _________________
a) resistive field
b) electrical field
c) magnetic field
d) capacitive field
Answer: magnetic field
4. The ability of an electronic system to function properly in its intended electromagnetic  environment and should not be a source of pollution to that electromagnetic environment is known as
a) Susceptibility
b) Emission
c) Interference
d) Electromagnetic compatibility
Answer: Electromagnetic compatibility
5. Electrical circuits are carriers of _________ as well as propagators of _____________ 
(i) electricity 
(ii) static field 
(iii) magnetic field
a) (i), (ii)
b) (ii), (iii)
c) (iii), (i)
d) (i), (iii)
Answer: (i), (iii)
6. Which of the following component/s utilize the the electromagnetic principle?
a) ge nerators
b) motors
c) relays
d) all of these
Answer: all of these. 
7. An electrical field is present whenever an electrical charge placed in a dielectric or insulatin g  medium experiences a force acting upon it.
a) True
b) False
Answer: True
8. Any electrical signal present in a circuit other than the desired signal is known as
a) Noise
b) Distortion
c) Interference
d)All of these
Answer: Noise
9. _________________ is the number of electric lines of flux passing through a unit area.
a) Magnetic flux density
b) Electric flux density
c) Magnetic flux intensity
d) Electric flux intensity
Answer: Electric flux density
10. Radiated interference is a computation level of EMI propagated in _______
a) electricity lines
b) copper wire
c) liquid
d) air
Answer: air
11. Attenuation is measured in _____________
a) amplitude
b) dB
c) watts
d) mV
Answer: dB
12. The effects of EMI can be reduced by
a) Suppressing emissions
b)  Reducing the efficiency of the coupling path
c)  Reducing the susceptibility of the receptor
d)All of these
Answer: All of these
13. _____ can also couple from one circuit to another by inductive or capacitive means
a) Transverse mode noise
b) Com mo n mode noise
c) Differential mode noise
d) Integral mode noise
Answer: Com mo n mode noise
14. Can we use filter made up of R-L-C combination for eliminating EMI?
a) Yes
b) No
Answer: Yes 
15. Power frequency fields fall in the category of
a) extra low frequency
b) super low frequency
c) very low frequency
d) low frequency
Answer: super low frequency
16. Whic h  of the following is no the way by which the propagated EMI is conductive?
a) air
b) power cable
c) signal wire
d) ground cable
Answer: air
17. Possible ways to minimize the EMI
a) filter
b) shielding
c) twisting the cables
d) all of these
Answer: all of these
18. ________ is the ration by which common mode signal is rejected
a) Common Mode Rejection  Ratio
b) rectification
c) decibel
d) attenuation
Answer: Common Mode Rejection  Ratio
19. Attenuation measured in ______
a) sec
b) decibels
c) mole
d) candela
Answer: decibels
20. Shielding is _______ to avoid unwanted noise from relating with a susceptible piece of equipment
a) Wire Shield
b) None of these
c) Magnetic enclosure
d)Metal enclosure
Answer: Metal enclosure
21. Electric field intensity (E) is a _____________ quantity
a) differential
b) vector
c) scalar
d) integral
Answer: vector
22. The opposite of susceptibility is
a) Immunity
b) Emission
c) Interference
d)Electromagnetic  co mpatibility
Answer: Immunity
23. The output power of the cascaded amplifier / attenuator system can be determined using
a) Actual gain of amplifier
b) Actual gain of amplifier and attenuator
c) Gain in dB of amplifier and attenuator
d) Actual gain of attenuator
Answer: Actual gain of amplifier  a nd attenuator
24. Any electrical signal present in a circuit other than the desired signal is known as
a) Noise
b) Distortion
c) Interference
d) All of these
Answer: Noise
25. In radiativ e  coupling, the emitter radiation field
a) Decays as 1 / R, where R is the separation distance between the emitter and the receptor
b) Decays as R, where R is the separation distance between the emitter and the receptor
c) Decays as 1 / 2 R, where R is the separation distance between the emitter and the receptor
d) Decays as 2R, where R is the separation distance between the emitter and the receptor
Answer: Decays as 1 / R, where R is the separation distance between the emitter and the receptor
26. The effects of EMI can be reduced by
a) Suppressing emissions
b) Reducing the efficiency of the coupling path
c) Reducing the susceptibility of the receptor
d) All of these
Answer: All of these
27. The man made noise sources is / are
a) Motors
b)Switches, radio interferences
c) Computers, digital electronics
d)  All of these
Answer: All of these
28. LISN is a device used to measure conducted emissions. LISN stands for
a) Line integrated stabilization network
b) Line impedance stabilization network
c) Line integrated stored network
d) Laser integrated stabiliz at ion networking
Answer: Line impedance stabilization network
29. For swept frequency measurements, the input impedance of the mismatched transmission line would vary with frequency as the electrical length of the transmission li ne  would
a) Decrease with frequency
b) Remains same with change in frequency
c) Increase with frequency
d) Either (a) or (b)
Answer: Increase with frequency
30. The ability of an electronic system to function properly in its intended electromagnetic environment and should not be a source of pollution to that electromagnetic environment is known as
a) Susceptibility
b) Emission
c) Interference
d) Electromagnetic compatibility
Answer: Electromagnetic compatibility
31. In EMC signal, the source delivers maximum power to the input of transmission line when the transmission line input impedance
a) Is equal to the source resistance
b) Greater than the source resistance
c) Smaller than the source resistance
d) None of these
Answer: Is equal to the source resistance