ELECTRICITY AND MAGNETISM FUNDAMENTALS Multiple Choice Questions Part 4

1 Who discovered the relationship between magnetism and electricity that serves as the foundation for the theory of electromagnetism?

Luigi Galvani
Hans Christian Oersted
Andre Ampere
Charles Coulomb

2 Who demonstrated the theory of electromagnetic induction in 1831?
Andre Ampere
James Clerk Maxwell
Charles Coulomb

3 Who developed the electromagnetic theory of light in 1862?
Heinrich Rudolf Hertz
Wilhelm Rontgen
James Clerk Maxwell
Andre Ampere

4 Who discovered that a current-carrying conductor would move when placed in a
magnetic field?
Andre Ampere
Hans Christian Oersted
Gustav Robert Kirchhoff

5 Who discovered the most important electrical effects which is the magnetic effect?
Hans Christian Oersted
Sir Charles Wheatstone
Georg Ohm
James Clerk Maxwell

6 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?
Luigi Galvani
Hans Christian Oersted
Charles Coulomb
Andre Ampere

7 Who discovered superconductivity in 1911?
Kamerlingh Onnes
Alex Muller
Geory Bednorz
Charles Coulomb

8 The magnitude of the induced emf in a coil is directly proportional to the rate of change of flux linkages. This is known as
Joule’s Law
Faraday’s second law of electromagnetic induction
Faraday’s first law of electromagnetic induction
Coulomb’s Law

9 Whenever a flux inking a coil or current changes, an emf is induced in it. This is known as
Joule’s Law
Coulomb’s Law
Faraday’s first law of electromagnetic induction
Faraday’s second law of electromagnetic induction

10 The force of attraction or repulsion between two magnetic poles is directly proportional to their strengths.
Newton’s first law
Faraday’s first law of electromagnetic induction
Coulomb’s first law
Coulomb’s second law

11 The force of attraction or repulsion between two magnetic poles is inversely proportional to the square of the distance between them. This is known as
Newton’s first law
Faraday’s first law of electromagnetic induction
Coulomb’s first law
Coulomb’s second law

12 The  branch of Engineering  which  deals  with the  magnetic  effect  of electric  current is
known as
Magnetism
Electromagnetism
Electrical engineering
Electronics engineering

13 The space outside the magnet where its pole have a force of attraction or repulsion on a
magnetic pole is called.
Electric field
Electromagnetic field
Free Space Field
Magnetic field

14 The total number of magnetic lines of force in a magnetic field is called.
Magnetic flux
Magnetic flux density
Magnetic flux intensity
Magnetic potential
Magnetic flux

15 The phenomenon by which a magnetic substance becomes a magnet when it is place near a magnet
Magnetic effect
Magnetic phenomenon
Magnetic induction
Electromagnetic induction

16 Which of the following magnetic materials can be easily magnetized in both direction?
Hard magnetic materials
High hysteresis loss materials
Low hysteresis loss materialsSoft magnetic materials
Soft magnetic materials

17 Hydrogen is an example of a  material.
Paramagnetic
Diamagnetic
Ferromagnetic
Non- magnetic

18 Cobalt is an example of a  material.
Paramagnetic
Diamagnetic
Ferromagnetic
Non- magnetic

19 What principle states that each electron in an atom must have a different set of quantum
numbers?
Inclusion principle
Exclusion principle
Quantum principle
Electron principle

20 The energy stored in an electrostatic field or electromagnetic field is called
Electromagnetic energy
Kinetic energy
Potential energy
Rest energy

21 Ohm’s law cannot be applied to which material?
Copper
Silver
Silicon carbide
Aluminum

22 What is the practical unit of electrical energy?
Watt
Kilowatt-hour
Kilowatt-second
Megawat-hour

23 Under ordinary conditions, a body is considered
positively charged
neutral
negatively charged
stable

24 A negatively charge body has
deficit of electrons
excess of protons
excess of electrons
deficit of neutrons

25 The unit of electrical energy is
Joule
Watt- second
Kilowatt- hour
All of these

26 Hysteresis   refers   to the______magnetizing force applied.
Ratio
Equality
Lagging effect
between flux density of the material and the

27 What is the relative permittivity of air?
0
1
⦁ 8.854 × 10^-12
⦁ 4n × 10^-7

28 In electro-mechanical conversion devices like generators and motors the reason why a
small air gap is left between the rotor and stator is to.
increase flux density in air gap
decrease the reluctance of magnetic path
permit mechanical clearance
complete the magnetic path

29 Permeance of a magnetic circuit is  the cross-sectional area of the circuit.
inversely proportional to
directly proportional to
dependent of
independent of

30 When a current carrying conductor is placed in a magnetic field, the maximum force will act on the conductor when the conductor is at an angle of  to the magnetic field.

45o
60o
30o
90o

31 Three charges of +5 C, -6 C and +9 C are placed inside a sphere. What is the total flux passing through the surface of sphere?
8 C
14 C
20 C
-6 C

32 The potential at a point due to a charge is 15 V. If the distance is increased three times, the potential at the point will be
5 V
18 V
45 V
15 V

33 The electric potential at a point in air due to a charge is 21 V. If the air is replaced by a
medium of relative permittivity of 3, then electric potential at that point will be
63 V
21 V
7 V
42 V

34 Refers to the non- metallic materials that have the ferromagnetic properties of iron.
Ferromagnetic
Diamagnetic
Ferrites
Paramagnetic

35 The air space between poles of magnets.
Free space
Air gap
Vacuum
Atmosphere

36 One that has magnetic poles produced by internal atomic structure with no external
current necessary
Diamagnetic
Permanent magnets
Paramagnetic
Electromagnetic

37 Magnetic effects of the earth as a huge magnet with north and south poles.
Diamagnetic
Ferromagnetic
Terrestrial magnetism
Terrestrial ferromagnetism

38 Used to maintain strength of magnetic field
Container
Air gap
Keeper
Source

39 Magnetic fields do not interact with
Moving permanent magnets
Stationary permanent magnets
Moving electric charges
Stationary electric charges

40 The magnetic field inside a solenoid
is zero
is uniform
increases with distance from the axis
decreases with distance from the axis

41 When the ferromagnetic substance is inserted in a current- carrying solenoid, the magnetic field is
Greatly decreased
Greatly increased
Slightly decreased
Slightly increased

42 The magnetic field of a bar magnet most closely resembles the magnetic field of
a horseshoe magnet
a straight current- carrying wire
a stream of electrons moving parallel to one another
a current- carrying wire loop

43 A permanent magnet does not exert a force on
an unmagnetized iron bar
a magnetized iron bar
a moving electric charge
a stationary electric charge

44 A current if flowing east along a power line. If the earth’s field is neglected, the direction of the magnetic field below it is
North
South
East
West

45 The emf produced in a wire by its motion across a magnetic field does not depend upon
the
Diameter of the wire
Length of the wire
Orientation of the wire
Flux density of the field

46 The magnetic flux through a wire loop in a magnetic field does not depend on
The area of the loop
The magnitude of the field
The shape of the loop
The angle between the plane of the loop and the direction

47 Paramagnetic substance has a relative permeability of
Slightly less than one
Equal to one
Slightly equal to one
Very much greater than one

48 A group of magnetically aligned atoms is called
Range
Lattice
Domain
Crystal

49 The ratio between the intensity of magnetization produced in a substance to the magnetizing force producing it
Magnetic Reluctivity
Magnetic Resistivity
Magnetic susceptibility
Magnetic conductivity

50 The lagging effect between flux density of the material and the magnetizing force applied
Permeance
Eddy current
Hysteresis
Reluctance