A step -down transformer is used on a 1000 V line to deliver 20 A at 120 V at the secondary coil. If the efficiency of the transformer is 80 % , the current drawn from the line is :

Options

A. 3A
B. 30 A
C. `0.3 A `
D. ` 2.4 A `

Answer

A

Explanation

` (80 )/(100)= ( 120 xx 20)/(1000 xx I_p) `
` I_p = (120 xx 20)/(1000 xx 0.8)= 3A `