Chapter 5 - Magnetic Fields Flashcards
What is the force on a wire proportional to
Flux density
How do you work out the size of the force on a length of wire
F = Bil
F = BQv
What is the unit for a tesla
Wb m^-2
Why are charged particles in a magnetic field deflected in a circular path
Force is perpendicular to direction of travel. Circular motion.
What is the force on a particle moving in a circular path
r = (mv) / (BQ)
What does it mean if the radius decreases
The particle is deflected more
What happens if the radius increases
The particle is deflected less
How do you work out magnetic flux
Φ = BA
What does the rate of change of flux linkage tell you
It induces a EM force of 1 volt in a loop of wire
What is Faraday’s Law
He induced emf is directly proportional to the rate of change of flux linkage
ε = N(Δφ/Δt)
What is Lenz’s law
The induced emf is always in such a direction to oppose the change that caused it
What is an alternator
A generator of alternating current
How do you work out flux linkage using angular speed
Nφ = BAN cos ω t
How do you work out induced emf using angular speed
ε = BAN ω sin ωt
How do you work out peak voltage
Vrms = Vo/squrt 2
