Question

can someone explain how an a.c. generator works?

Answer 1

A conducting coil of area A is placed in a magnetic field B. An ignition process rotates it initially. When it is an angle θ with its initial line, the flux through it equals

φ = BAcosθ
θ= ωt angular velocity x time
φ=BAcosωt
EMF = -dφ/dt
= ωBAsinωt

Current I = E/R, R is the resistance of the loop
hence
I = (ωBA/R)sin ωt
which is the expression for the generated alternating current