magnetic field

Question 1

magnetic flux density

Answer 1

force acting per unit current per unit length on a straight conductor placed at right angles to the magnetic fields

Question 2

features of magnetic fields

Answer 2

• goes from north to south pole
• never touch and cross
• depends on closeness of the line
• arrow shows the direction at which a free magnetic north pole would move if placed at a point

Question 3

conditions for a charge to experience a magnetic force when placed in a magnetic field

Answer 3

1. charge must be moving
2. velocity of the charge must have a component that is perpendicular to the direction of the magnetic field

Question 4

a current-carrying conductor produces a magnetic field when:

Answer 4

1. 2 conductors carry current and each lies in the magnetic field of the other
2. interaction causes a force between conductors

Question 5

hall effect

Answer 5

occurs when a current-carrying conductor or semiconductor is placed in a magnetic field

Question 6

motor effect

Answer 6

when a current-carrying conductor is at an angle to a magnetic field

Question 7

magnetic field

Answer 7

a region of space where a force is experienced by either moving charges or by permanent magnets

Question 8

magnetic flux

Answer 8

measure of the amount of magnetic field passing through a surface

Question 9

magnetic flux linkage

Answer 9

occurs when a coil with N turns experiences magnetic flux

Question 10

how to increase the size of an induced EMF and current

Answer 10

• increase rate of change of magnetic flux (moving magnet/coil faster to each other)
• stronger magnet
• increase number of turns in the coil

Question 11

faraday’s law of electromagnetic induction

Answer 11

states that an emf is induced in a circuit when the magnetic flux linkage through the circuit changes with time

Question 12

Lenz law

Answer 12

the direction of an induced emf is such that it opposes the change the produces it (magnetic field)

Question 13

why is the slice of material used in a hall voltage thin

Answer 13

• vH is inversely proportional to thickness
• t needs to be small for vH to be large enough to measure