Electromagnetic Induction Flashcards
What is electromagnetic induction?
Moving a wire in correlation with a magnetic field (or vice versa), creating an emf
What is changing current?
Current changing from + to -
or
Current turning on
What is self induction?
Changes in flow of current in a coil are opposed by the coil itself
What is mutual induction?
An emf being induced in a coil due to current flowing in an adjacent coil
What is the equation for inductance?
L = (N x Φ) / I
inductance = (no. turns x flux) / current
What is the equation for energy?
W = 1/2 x L x I^2
energy = 1/2 x inductance x current^2
What is the equation for an induced emf?
E = B x l x v
induced emf = flux density x length x velocity
What is the equation for induced emf in the opposite direction?
E = - N (dΦ / dt)
What is Lenz’s law?
Current induced in a circuit is in the opposite direction to change in flux and exerts mechanical force which opposes the motion
What is Faraday’s law?
Electromotive force is equal to the negative of the time rate of change of the flux
What is the equation for induced voltage?
ε = - (dΦ x B) / dt
What is the the equation relating voltage and no. turns in a coil in transformers?
Vp / Vs = Np / Ns
primary voltage / secondary voltage = primary number of turns / secondary number of turns
What is the equation for force in a single wire?
F = B x I x l
(2nd l being length)
What is the equation for torque in a coil?
T = B x A x N x I
torque = flux density x area x no. coils x current
