Question

A transformer is used to light a lamp rated 40w, 240v from a 400v A.C supply. Calculate:
A. The ratio of the number of turns of the primary to the secondary coil.
B. Current drawn from the main circuit if the efficiency of the transformer is 90%.​

Answer 1

Answer:1.81

(a) Explanation:the turn ratio= input voltage÷output voltage.

400÷220=1.81.

Don't know how to solve b part...