Transformer primary-to-secondary turn ratio problem

[physics100000]

Homework Statement

A step down transformer has a primary to secondary ratio of 4:1. If the peak current in the secondary is 12 A, the peak current in the primary is what?

Homework Equations

Vp/Vs = Np/Ns

The Attempt at a Solution

(4/1) = (Ip/12 A)

what is the relation between I and V? (V= IR or V= IP does not seem to work).

thanks in advance!

 

[kuruman]

In an ideal transformer the power in the primary is the same as in the secondary, P₁ = P₂. You know that P = IV, so ...