Which expression is right about EMF equation of a transformer if f = frequency, N1 = number of turns in primary, ϕm = maximum flux in a core, A = iron area, Bm = maximum flux density?
1
E = 4.44 f N1 ϕm
2
E = 4.44 f N1 Bm
3
E = 4.44 f N1 ϕmA
4
E = 4 f N1 ϕmA