5.5 Magnetic Fields

Question 1

Magnetic flux density, B. Definition

Answer 1

‘The force per unit current carrying length’

Question 2

Tesla definition

Answer 2

‘One Tesla is the magnetic flux density which will cause a conductor 1m long, carrying a current of 1A, to experience a force of 1N’

Question 3

Faradays law definition and equation

Answer 3

‘Induced emf directly proportional to the rate of change of flux linkage’

€=-N#%/#t

%=flux linkage
#=change in

Question 4

Lenz’s law

Answer 4

‘The direction of the induced current is such that it opposes the change in magnetic flux that is producing it’

Question 5

Fleming left hand rule

Answer 5

Thumb= motion
First finger= magnetic field
Second finger= current

Question 6

Force equation

Answer 6

F=B.I.L

Question 7

Magnetic flux equation

Answer 7

%=BA
Unit=Wb

Question 8

Magnetic flux equation with N turns

Answer 8

N.%=NBA

Question 9

Flemings right hand rule

Answer 9

Thumb=motion
First finger=magnetic field
Second finger= current

LHR: RHR:
F<—produced. F✔️
B✔️. B✔️
I✔️. I<—produced

Question 10

Induced emf equation

Answer 10

€=-NBA/t