To demonstrate Faraday’s law of electromagnetic induction 1, 2 and 3 To demonstrate Lenz’s law To compare rms and peak values of a.c. To demonstrate self-induction To demonstrate the operation of a transformer
Formulae: Magnetic flux: Φ = BA Faraday’s law of electromagnetic
induction: E ∝ Change in Φ Φ2 – Φ1
________________ t
E ∝
__________ t
____ √__
Ia.c. 2
or E = −N dΦ
____ dt
Alternating current rms conversion: Irms =
Ia.c. = Irms × √
__ 2
LEAVING CERTIFICATE PHYSICS 313
CHAPTER 28 CHECKLIST Va.c.
Vrms =
_____ √
__ 2
Va.c. = Vrms × √
___ Vo
=
___ Ns
Np
__ 2
Magnetic flux formula
Derivation of E =
F2 –F1 dt
Mutual induction
Self-induction
Back emf
Induction and uses
P = Irms × Vrms P = I2
rms × R
Step-up/step-down conversion: Vi
Derivation: E = – dΦ
____ dt
Laws: Faraday’s law, Lenz’s law Scientists: Faraday, Lenz
STS: magnetic effects on circuits, uses of EM induction in power generation and dynamos, back emf circuit problems, transformer use and design
