Question

A step down transformer has a turn ratio of `20 : 1`. If 8 volt are developed across `0.4 Omega` secondary, then the primary current will be:
A. `1 A`
B. `2 A`
C. `4 A`
D. `0.5 A`

Answer 1

Correct Answer - A
`(n_p)/(n_s) = 20/1 = (V_p)/(V_s) = (I_s)/(I_p)`
`:. I_(s) = 8/(4//10) = 20 A :. I_(p)=I_(s) xx 1/20 = 1A`.