Electromagnetism

Question 1

Magnetic Flux (ф)

Answer 1

Ф = BA cosѲ that is the flux density (number of lines of magnetic flux) passing through a particular area.

Question 2

Weber (Wb) - Tesla x m2 (as T = Wb/m2)

Answer 2

The unit of Magnetic Flux or Magnetic flux linkage is the Weber.

Question 3

Magnetic Flux Linkage

Answer 3

The product of the magnetic flux and the number of turns (linking) it.
Magnetic Flux Linkage (NФ) = BAN cosѲ.

Question 4

Force on a charge Q

Answer 4

F = BQv sinѲ Force on a charge Q moving at velocity v at an angle Ѳ to a field B

F = Bev May be an easier way to recall BIL, Bev and BAN.

Question 5

Faraday’s Law (- sign to accommodate Lenz’s law)

Answer 5

The magnitude of the induced emf is proportional to the rate of change of magnetic flux linkage.

E = - Δ(N Ф) / Δt = rate of change of Magnetic Flux Linkage.

Question 6

Lenz’s Law

Answer 6

Any induced current or induced emf will be established in a direction so as to produce effects which oppose the change that is producing it.
Note: imagine Left hand rule and Right hand rule together fighting to take effect….