electromagnetism Flashcards
equation for magnetic flux density (B)? (Φ, A)
B = Φ/A
where Φ = magnetic flux and A = cross-sectional area (perpendicular to magnetic flux)
equation for magnetic flux (Φ)? (B, A)
Φ = BA
where B = magnetic flux density and A = cross-sectional area (perpendicular to magnetic flux)
equation for flux linkage (NΦ)? (N, B, A)
NΦ = BAN
(don’t actually times by N twice, NΦ is just one of the ways of writing flux linkage)
where N = number of coils and BA = magnetic flux (B = magnetic flux density and A = cross-sectional area)
equation relating current (I), conductance (G) and voltage (V)
I = GV
equation for permeance (Λ) of core? (µ, A, l)
Λ = µA/l
where µ = permittivity of material of core, A = cross-sectional area of core and l = length of core
equation for magnetic flux (Φ)? (Λ, N, I)
Φ = ΛNI
where Λ = permeance, N = number of turns on coil and I = current
‘equation’ for faraday’s law?
ε = dNΦ/dt
OR
ε ∝ dNΦ/dt
where ε = induced emf, NΦ = flux linkage and t = time
‘equation’ for lenz’s law?
ε = - (dNΦ/dt)
OR
ε ∝ - (dΦ/dt)
minus sign makes it lenz’s law bc “emf is induced in direction such that it opposes change causing it”
equation for induced emf (ε)? (B, l, v)
ε = Blv
where B = magnetic flux density, l = length of wire cutting perpendicular to magnetic field and v = speed at which wire cuts through magnetic field
size of force (F) exerted on charged particles flowing through wire perpendicular to magnetic field? (B, I, l)
F = BIl
where B = magnetic flux density, I = current and l = length of wire cutting perpendicular through magnetic field
equation linking ratio of V in primary coil to V in secondary coil, ratio of N of turns on primary coil to N of turns on secondary coil and ratio of I in secondary coil to I in primary coil?
Vp/Vs = Np/Ns = Is/Ip
equation for voltage in secondary coil (Vs)? (Vp, Np, Ns)
Vs = (Vp/Np) x Ns
