Electromagnetism

Question 1

Why are iron cores used in transformers?

Answer 1

Have high magnetic permeability so are able to concentrate the magnetic flux.

Question 2

Define Magnetic Flux

Answer 2

1 Amount of magnetic field passing through a surface.
Unit Weber, wb

2 B X Area normal to the field

Question 3

Define Magnetic Flux Density

Answer 3

Magnetic flux passing, perpendicular, through unit area.

Unit Tesla, T.

Question 4

Define Magnetic Flux Linkage

Answer 4

Product of the magnetic Flux and number of turns on the coil that it passes through. Unit Wb Turns.

Question 5

Define Lenz’s Law

Answer 5

The direction of any induced current is in a direction that opposes the flux change that caused it.

Question 6

Define a Velocity selector

Answer 6

Device that uses both electric and magnetic fields to select charged particles of specific velocities

Question 7

Define electromagnetic induction

Answer 7

Process of inducing an emf in a conductor when there’s a change in magnetic flux linkage across the conductor

Question 8

Define search coil

Answer 8

Small, flat coil used to determine the strength of a magnetic field

Question 9

Transformer

Answer 9

Device that can either increase or decrease the size of an alternating voltage with little loss of power