A transformer working on `220 V` a.c. line gives an output current of `4 A` at `55 V`. What is the primary current (in ampere) ? Assume that there is no loss of energy.

Answer

1

Explanation

Here, `E_(P) = 220 V, I_(s) = 4 A, E_(s) = 55 V, I_(P) = ?`
As there is no loss of energy, `:. E_(P) I_(P) = E_(s) I_(s)`
`I_(P) = (E_(s) I_(s))/(E_(P)) = (55 xx 4 )/(220) = 1 A`