1000+ Electricity Fundamentals MCQ for NMAT [Solved]

1. Mmf in a magnetic circuit corresponds to _____ in an electric circuit
A. Emf
B. Voltage drop
C. Electric Field Intensity
D. Potential gradient
Answer : A

2. The electric field intensity between the parallel plate air capacitor is 20 N/C. If an insulating slab of relative permittivity 5 is placed between the platesa then electric field intensity will be
A. 20 N/C
B. 100 N/C
C. 4N/C
D. 40 N/C
Answer : C

3. Paramagnetic substance has a relative permeability of
A. Slightly less than one
B. Equal to one
C. Slightly equal to one
D. Very much greater than one
Answer : C

4. The emf induced in a coil due to the changing current of another neighboring coil is called
A. Mutually induced emf
B. Self induced emf
C. Statically induced emf
D. Dynamically induced emf
Answer : A

5. Electric field intensity is measured in
A. volts/meter
B. Newton/meter
C. Newton-meter
D. Amperes/meter
Answer : A

6. If the value of 0 a conductor is 1/234 per oCa then the value of 18is
A. 1/218 per oC
B. 1/252 peroC
C. 1/272 per oC
D. 1/273 per oC
Answer : B

7. The magnetic flux of 2000 lines is how many Maxwells?
A.
B.
C.
D.
Answer : B

8. The customary energy unit in atomic and nuclear physics is
A. Joule
B. Volt- coulomb
C. electron-volt
D. Walt- second
Answer : C

9. Residual magnetism refers to the flux densitya which exists in the iron core when the magnetic field intensity is
A. Minimized
B. Reduced to zero
C. Maximize
D. Unity
Answer : B

10. Who demonstrated that there are magnetic effects around every current-carrying conductor and that current-carrying conductors can attract and repel each other just like magnets?
A. Luigi Galvani
B. Hans Christian Oersted
C. Charles Coulomb
D. Andre Ampere
Answer : D

11. Electric field intensity at a point is numerically equal to ________ at that point.
A. potential gradient
B. potential difference
C. dielectric constant
D. the force
Answer : D

12. Refers to the magnetic lines
A. Flux
B. Hysteresis
C. Current
D. Magnetomotive force
Answer : A

13. An alloy of 40 percent iron and 60 percent nickel.
A. Alnico
B. Permalloy
C. Hipernik
D. Manganin
Answer : C

14. Permeance of a magnetic circuit is _________ the cross-sectional area of the circuit.
A. directly proportional to
B. inversely proportional to
C. dependent of
D. independent of
Answer : A

15. A 6- V battery is connected across a solenoid of 100 turns having a resistance of 2 ?a Calculate the number of ampere turns?
A.
B.
C.
D.
Answer : C

16. Magnetic fields do not interact with
A. Moving permanent magnets
B. Stationary permanent magnets
C. Moving electric charges
D. Stationary electric charges
Answer : D

17. Hysteresis loss can be reduced by one of the following.
A. Increasing mmf of the circuit
B. Using material narrow hysteresis loop
C. Using ferromagnetic core
D. Laminating the magnetic circuit
Answer : B

18. A law that states that the current in a thermionic diode varies directly with the three- halves power of anode voltage and inversely with the square of the distance between the electrodesa provided operating conditions are such that the current is limited only by the space charge.
A. Hall's law
B. Joule's law
C. Child's law
D. Coulomb's law
Answer : C

19. What is the SI unit of conductance?
A. Siemens
B. Mhos
C. Ohms
D. 1/Ohms
Answer : A

20. What is the main advantage of temporary magnets?
A. The magnetic flux can be changed.
B. Hysteresis can be decreased.
C. Magnetic materials can be used.
D. Abundance of ferromagnetic material that can be temporarily magnetized.
Answer : A

21. The hot resistance of an incandescent lamp is about _______ its cold resistance.
A. 10 times
B. 100 times
C. 5 times
D. 50 times
Answer : A

22. Which of the following is a vector quantity?
A. Magnetic potential
B. Magnetic field intensity
C. Magnetic permeability
D. F lux density
Answer : B

23. A law stating that the magnetic susceptibilities of most paramagnetic substances are inversely proportional to their absolute temperatures.
A. Curie's Law
B. Child's Law
C. CR Law
D. Curie-Weiss Law
Answer : A

24. A 200-watt lamp working for 24 hours will consume approximately _____ units.
A.
B.
C.
D.
Answer : B

25. One weber of flux is equal to _______ magnetic lines of force.
A. 10^6
B. 10^10
C. 4 × 10^7
D. 10^8
Answer : D

26. What is the cgs unit of magnetomotive force?
A. Gilbert
B. Ampere- turn
C. Maxwell
D. Weber
Answer : A

27. The force between two magnetic poles is _____ the relative permeability of the medium.
A. directly proportional to
B. independent of
C. inversely proportional to
D. equal to
Answer : C

28. The direction of force o a current carrying conductor placed in a m found by
A. Cork screw rule
B. Fleming's left hand rule
C. Fleming's right hand rule
D. using a compass
Answer : B

29. Back emf refers to the
A. Current equal to the applied emf
B. Opposing emf
C. Current opposing the applied emf
D. Voltage opposing the applied emf
Answer : D

30. The temperature coefficient of resistance of semiconductors is
A. positive
B. zero
C. negative
D. infinite
Answer : C

31. Referred to as the specific reluctance of a material
A. Resistivity
B. Reluctivity
C. Conductivity
D. Permeability
Answer : B

32. What is the practical unit of electrical energy?
A. Watt
B. Kilowatt-hour
C. Kilowatt-second
D. Megawathour
Answer : B

33. Hysteresis is a phenomenon of _________ in a magnetic circuit.
A. setting up constant flux
B. lagging of H behind B
C. lagging B behind H
D. leading B ahead H
Answer : C

34. A one cubic cm of copper has how many free electrons at room temperature?
A. 80 × 10^18
B. 8.5 × 10^22
C. 20 × 10^10
D. 50 × 10^20
Answer : B

35. When the relative permeability of a material is much greater than 1a it is called _______ material.
A. diamagnetic
B. ferromagnetic
C. paramagnetic
D. non-magnetic
Answer : B

36. The diameter of a hydrogen atom is approximately ______ cm.
A. 1.1 x 10^-6
B. 1.1 x 10^7
C. 1.1 x 10^-8
D. 1.1 x 10^-9
Answer : C

37. There are how many compounds available in nature?
A.
B.
C. 300a000
D. Unlimited
Answer : D

38. Whenever a conductor cuts magnetic fluxa an emf is induced in it. This is known as
A. Coulomb's law
B. Joule's law
C. Faraday's law
D. Ohm's law
Answer : C

39. The temperature coefficient of resistance of conductors is
A. positive
B. zero
C. negative
D. infinite
Answer : A

40. The total number of magnetic lines of force in a magnetic field is called
A. Magnetic flux
B. Magnetic flux density
C. Magnetic flux intensity
D. Magnetic potential
Answer : A

41. A group of magnetically aligned atoms is called
A. Range
B. Lattice
C. Domain
D. Crystal
Answer : C

42. One oersted (Oe) is equivalent to _____ Gb/cm.
A.
B.
C.
D.
Answer : A

43. How many turns are needed to produce a magnetomotive force of 1000 A.t for a coil with 6 amperes?
A. 6000 turns
B. 600 turns
C. 167 turns
D. 67turns
Answer : C

44. Defined as the ratio of the volume occupied by the atoms or ions in a unit cell divided by the volume of the unit cell and is used to measure the compactness of a crystal.
A. Atomic packing factor (APF)
B. Ionic Packing Ratio (IPR)
C. Atomic compacting factor (ACF)
D. Ionic compacting ratio (ICR)
Answer : A

45. The B-H curve for ________ is a straight line passing through the origin.
A. cobalt
B. air
C. hardened steel
D. soft iron
Answer : B

46. A magnetic field is
A. The current flow through space around a permanent magnet
B. The force set up when current flows through a conductor
C. The force that drives current through a resistor
D. The force between the plates of a charged capacitor
Answer : B

47. If two similar charges 1 coulomb each are placed 1 m apart in aira then the force of repulsion is
A. 8 × 10^6 N
B. 9 × 10 ^9 N
C. 10^6 N
D. 5 × 10^6 N
Answer : B

48. What determines the value of the temperature coefficient of resistance of a material?
A. length
B. cross-sectional area
C. volume
D. nature and temperature
Answer : D

49. Under ordinary conditionsa a body is considered
A. positively charged
B. neutral
C. negatively charged
D. stable
Answer : B

50. The ability of a material to conduct magnetic flux through it.
A. Permittivity
B. Reluctivity
C. Conductivity
D. Permeability
Answer : D