Deck 13: Electromagnetism

Question 1

A conductor that carries an electric current is surrounded by a

A) perpendicular electric field
B) concentric electric field
C) perpendicular magnetic field
D) concentric magnetic field

Answer 1

concentric magnetic field

Question 2

A dot shown within a circle representing an end-on view of a conductor is the convention used to indicate that current is

A) flowing towards you
B) flowing away from you

Answer 2

flowing towards you

Question 3

The 'direction' of lines of magnetic flux are determined by the direction a __________ would point when placed within the field

A) permanent magnet
B) compass needle
C) gaussmeter

Answer 3

compass needle

Question 4

The SI unit of measurement for magnetic flux is the

A) weber
B) tesla
C) gauss
D) maxwell

Question 5

For conventional flow, the direction of the magnetic field surrounding a straight conductor can be determined using the

A) corkscrew' rule
B) right-hand 'grip' rule
C) either of the above

Question 6

What is the magnetic polarity of the visible face of a loop of wire, around which conventional flow is counter-clockwise?

A) north
B) south

Question 7

The magnetic polarity of a coil, around which conventional current direction is known, may be determined using

A) Fleming's Right-Hand Rule
B) Fleming's Left-Hand Rule
C) the right-hand 'grip' rule
D) the left-hand 'grip' rule

Question 8

If each of two parallel conductors carry currents flowing in the same direction, then the two conductors

A) will repel each other
B) will attract each other
C) will have no effect upon each other

Question 9

Flux density is defined as the

A) flux per unit area, measured in webers
B) flux per unit area, measured in teslas

Question 10

The SI unit of measurement for magnetic flux density is the

A) weber
B) tesla
C) gauss
D) maxwell

Question 11

Magnetic flux density is at its greatest __________ the poles of an electromagnet

A) closest to
B) furthest away from

Question 12

Which has the greatest effect on increasing the flux density within a current-carrying coil?

A) doubling the number of turns
B) halving the cross-sectional area
C) reducing its length by half
D) inserting an iron core

Question 13

When using Fleming's Left-Hand Rule, the first finger represents __________, the second finger represents __________, and the thumb represents __________

A) force, field, current
B) field, current, force
C) current, force, field

Question 14

A current-carrying conductor, placed within a permanent magetic field, will be forced out of that field. This is an example of

A) motor action
B) generator action
C) electromagnetic induction

Question 15

Motors, moving-coil measuring instruments, and dynamic loudspeakers all work on the principle of

A) motor action
B) generator action
C) electromagnetic induction

Question 16

The components of a d.c. motor which ensure that the rotor continues to rotate in the same direction are the

A) slip rings and brushes
B) split-ring commutator and brushes
C) diodes