A power transmission line feeds input power at 2300 V a step down transformer with its primary windings having 4000 turns. The output power is delivered at 230 V by the transformer. If the current in the primary of the transformer is 5A and its efficiency is `90%`, the output current would be :

Options

A. 20 A
B. 40 A
C. 45 A
D. 25 A

Answer

C

Explanation

Given: `V_(P) = 2300 V, V_(s) = 230 V, I_(p) = 5A, N = 90% = 0.9`
Efficiency `n = 0.9 = (P_(s))/(P_(p)) Rightarrow P_(s) = 0.9 P_(p)`
`V_(s) I_(s) = 0.9 xx V_(P)I_(p) (because P = VI)`
`I_(s) = (0.9 xx 2300 xx 5)/(230) = 45 A`