A `220 V` input is supplied to a transformer. The output circuit draws a current of `2.0 A` at `440 V`. If the efficiency of the transformer is `80%`, the current drawn by the primery winding of the transformer is

Options

A. 3.6 ampere
B. 2.8 ampere
C. 2.5 ampere
D. 5.0 ampere

Answer

D

Explanation

`eta =(V_SI_S)/(V_P I_P)`
`I_P = (V_S I_S)/(eta V_P) = ((440V)(2A))/((80/100) (220V)) = ((440V)(2A)(100))/((80)(220V)) = 5A`