1000+ Electricity Fundamentals Multiple Choice Question Answer [Solved]

1. Whenever a flux inking a coil or current changesa an emf is induced in it. This is known as
A. Joule's Law
B. Coulomb's Law
C. Faraday's first law of electromagnetic induction
D. Faraday's second law of electromagnetic induction
Answer : C

2. 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

3. If a magnetic flux cuts across 200 turns at a rate of 2Wb/sa the induced voltage according to Faraday's law is about
A. 400 V
B. 100 V
C. 200 V
D. 600 V
Answer : A

4. When the current flowsa the magnetic field ��. conductor is in what direction?
A. The same as the current direction
B. Opposite the current direction
C. Omnidirectional
D. In the direction determined by the left hand rule
Answer : D

5. The science of adapting electronics to aerospace flight.
A. Avionics
B. Aerotronics
C. Aerodynamics
D. Astrionics
Answer : D

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

7. The reluctance of a magnetic circuit varies with
A. length × area
B. area � length
C. length � area
D. length + area
Answer : C

8. 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

9. The amount of magnetizing force to counter balance the resid magnetic material is referred to as
A. Reluctivity
B. Susceptivity
C. Coercivity
D. Retentivity
Answer : C

10. The ratio between the intensity of magnetization produced in a substance to the magnetizing force producing it
A. Magnetic Reluctivity
B. Magnetic Resistivity
C. Magnetic susceptibility
D. Magnetic conductivity
Answer : C

11. 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

12. Flux density is measured in
A. Tesia
B. Weber
C. Ampere- turn
D. Maxwell
Answer : A

13. A t/m is a unit of
A. Mmf
B. Emf
C. Reluctance
D. Magnetizing force
Answer : D

14. Permanent magnets can be found in
A. electric bells
B. earphones
C. relays
D. dy namic loudspeakers
Answer : B

15. The conduction of electricity across the surface of a dielectric is called
A. creepage
B. skin effect
C. surface effect
D. crosstalk
Answer : A

16. Hysteresis refers to the ______ between flux density of the material and the magnetizing force applied.
A. Leading effect
B. Ratio
C. Equality
D. Lagging effect
Answer : D

17. A commercial alloy of aluminum nickela and iron with cobalta copper and titanium added to produce about 12 grades.
A. Alnico
B. Brass
C. Aluminum
D. Constantan
Answer : A

18. The current of electric circuit is analogous to which quantity of a m
A. Mmf
B. Flux
C. Flux density
D. R eluctivity
Answer : B

19. The B-H curve of ________ is not a straight line.
A. air
B. wood
C. silicon steel
D. soft iron
Answer : D

20. Amorphous solid is also called
A. Crystalline
B. Non- crystalline
C. Polycrystalline
D. Homogenous
Answer : B

21. If the distance between two magnetic poles decreases by 2 timesa the force between them
A. decreases two times
B. increases four times
C. increases two times
D. decreases four times
Answer : B

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

23. The force between two charges placed a given distance apart ______ as the relative permittivity of the medium is increased.
A. increases
B. decreases
C. remains unchanged
D. becomes infinite
Answer : B

24. ______ is an electromagnet with its core in the form of a close magnetic ring.
A. S olenoid
B. Paraboloid
C. Toroid
D. Cycloid
Answer : C

25. How is mutual inductance between two coils decreased?
A. By using a common core
B. By moving the coils closer
C. By moving the coils apart
D. By increasing the number of turns of either coil
Answer : C

26. The uncharged particles which have no effect on its atomic charge.
A. Nucleons
B. Electrons
C. Protons
D. Neutrons
Answer : D

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

28. When a conductor is stationary and the magnetic field is moving or changing the emf induced is called
A. Statically induced emf
B. Mutually induced emf
C. Self induced emf
D. Dynamically induced emf
Answer : A

29. If you hold the conductor with right hand so that the stretched thumb points in the direction of the currenta then encircling fingers will give the direction of magnetic lines of force round the conductor. This is known as
A. Left hand cork screw rule
B. Right hand cork screw rule
C. Left hand rule
D. Right hand rule
Answer : D

30. Calculate the permeability (in T/A. t/m) of a magnetic material that has a relative permeability of 300
A. 3.78 x 10^4
B. 3.78 x 10^-5
C. 3.78 x 10^-3
D. 3.78 x 10^-6
Answer : A

31. What is the value of the absolute permittivity of air?
A. 8.854 F/m
B. 8.854 × 10^-12 mF/m
C. 8.854× 10^-12 F/m
D. 8.854 × 10^-12 F/m
Answer : C

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

33. A length of wire has a resistance of 10 ohms. What is the resistance of a wire of the same material three times as long and twice the cross-sectional area?
A. 30 ohms
B. 20 ohms
C. 15 ohms
D. 7 ohms
Answer : C

34. One that has magnetic poles produced by internal atomic structure with no external current necessary
A. Diamagnetic
B. Permanent magnets
C. Paramagnetic
D. Electromagnetic
Answer : B

35. Defined as the number of lines per unit area through any substance in a plane at right angles to the lines of force
A. Flux
B. Flux lines
C. Flux density
D. Flux intensity
Answer : C

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

37. Hipernik is an alloy containing __________ iron and __________ nickel.
A. 40% ; 60%
B. 60% ; 40%
C. 50% ; 50%
D. 70% ; 30%
Answer : A

38. The force of attraction or repulsion between two magnetic poles is directly proportional to their strengths.
A. Newton's first law
B. Faraday's first law of electromagnetic induction
C. Coulomb's first law
D. Coulomb's second law
Answer : C

39. Electromotive force in a circuit
A. causes free electrons to flow
B. increases the circuit resistance
C. maintains circuit resistance
D. is needed to make the circuit complete
Answer : A

40. The evaporation of electrons from a heated surface is called
A. Radiation
B. Convection
C. Thermionic emission
D. Conduction
Answer : C

41. What is the diameter of an atom?
A. About 10^-10 m
B. About 10^-10 cm
C. About 10^-10 mm
D. About 10^-10 �m
Answer : A

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

43. The force acting on a unit n- pole placed at that point is called
A. Magnetic field intensity
B. Electric field intensity
C. Electromagnetic field intensity
D. Intensity magnetization
Answer : A

44. When a wire loop is rotated in a magnetic field the direction of the induced emf changes one in every _______ revolution
A.
B.
C.
D.
Answer : B

45. 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

46. The electric potential across part AB of a circuit is 5 V; point A being at higher potential. If a charge of 5 Cmoves from A to Ba then energy released as
A. 5 joules
B. 25 joules
C. 10 joules
D. 100 joules
Answer : B

47. One of the solid structures in which the position of the atoms or ions are predetermined
A. Crystalline solid
B. Amorphous solid
C. Polycrystalline solid
D. Poly amorphous solid
Answer : A

48. 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

49. Permeability means
A. The conductivity of the material for magnetic lines of force
B. The magnetization test in the material after exciting field has been removed
C. The strength of an electromagnet
D. The strength of the permanent magnet
Answer : A

50. Lenz's law is the consequence of the law of conservation of
A. Energy
B. Charge
C. Field lines
D. Momentum
Answer : A