Electromagnetism Flashcards
1
Q
Define magnetic flux density and what is the unit
A
The force on 1 metre of wire carrying a current of one amp at right angles to the magnetic field
Tesla
2
Q
Suggest why it is impossible for overhead cables carrying an alternating current to float in the earths magnetic field
A
Force on the cables will keep changing direction due to alternating current
3
Q
Define magnetic flux
A
Magnetic flux density x area normal to the field
4
Q
Faradays law
A
The induced e.m.f. Is directly proportional to the rate of change of flux linkage
5
Q
Lenzs law
A
The induced e.m.f. Is always in such a direction as to oppose the change that caused it
6
Q
Principles of a velocity selector
A
- Magnetic field tries to deflect particles upwards (F=BQv)
- Electric field tries to deflect particles downwards (F=EQ)
