Principle:

A transformer is a static electrical apprentices by means of which electric power in one circuit is transformed into electric power of the same frequency in another circuit. It can raise or lower the voltage in a circuit but with a corresponding decrease or increase in current. The physical basis of a transformer is mutual induction between two coils linked by a common magnetic flows. In its simplest form it consists of 2 inductive coils. Which are electrically separated but magnetically linked by a path of low reluctance. The 2 coils possess high mutual inductance if one coil is connected to a source of alternate voltage, an alternating flows is set up in the laminated core most of which is connected to other coil junction which if produces mutually induced emf. If the 2nd coil circuits is closed using a load then a current flows in it, in which electric energy is fed from theca supply is called primary winding and other from which the energy is supplied to the load is called secondary winding.

$(II)Ø=Øm \sin wt$

By faraday’s law of electromagnetic induction, emf induced in a transformer,

$e=\dfrac{Nd\emptyset}{dt} \\ \text{By leny's law} \\ e=\dfrac{-Nd\emptyset}{dt} \\ \therefore e=\dfrac{-Nd}{dt}\emptyset_m \sin wt \\ =-N2 \pi f \times . \emptyset_m \cos wt \\ N\times2 \pi f \times \emptyset_m \times (-\cos wt) \\ e=N2 \pi f . \emptyset_m \sin (wt-90^0) \\ I_{\max}=2 \pi f. \emptyset_m \\ E_{RMS}=E=\dfrac{E_{RMS}}{\sqrt2}=4.44 fn\emptyset_m$