physics ques. please help me?

Question

A transformer on a pole near a factory steps the voltage down from 3600 V (rms) to 120 V (rms). The transformer is to deliver 1000 kW to the factory at 94% efficiency. Find values for the following.
(a) the power delivered to the primary
kW
(b) the current in the primary
A
(c) the current in the secondary
A

Answer 1

Ok, let's remember this :

V1*I1 = V2*I2

V1 = primary voltage

V2 = secondary voltage

I1 = primary current

I2 = secondary current

If the secondary delivers 1000 kW at 94%

efficiency = 94 % = secondary power / primary power*100%

94 = (1000 Kw / P1)*100

P1 = 1063.8 Kw

the current in the primary : 1063.8 = 3600*I1

I1 = 0.29 A

the current in the secondary :

0.29*3600 = 120*I2

I2 = 8.7 amperes

Hope that helped