Gr.11 physics help! PLEASE?

Question

Please help me solve these, i having a really difficult time and need someone to walk me through the steps to solve it

thnk you

2) A power station has output of 5.00 x 10^3 MW. This is transmitted equally over 20 lines from generating station to electric substation where it undergoes first stepdown for delivery into your home. The transformers at the substation have 6000 turns in primary coils and 400 turns in secondary coils. Each line from generating station supplies eletricity to 1 transformer. Primary voltage to the transformer is 4.50 x 10^5 V.

What is the current output of the transformer (assume 100% efficiency)

Answer 1

2 rules are to be used, the first one is:

1- V primary/ V secondary = No of turns primary/ No of turns Secondary

so:

Vp /Vs = Np /Ns

Vs= [ Ns *Vp ] /Np

--------

2ns one is:

2- Power (W)= Voltage (V) * current (A)

P=VI

--------------------------------

SO :

Vs= [ Ns *Vp ] /Np

once you find out the Vs here, you can use it in the next formula which is:

P = V(secondary)* I (secondary)

I (secondary)= P /V(secondary)

these are the formulas you should use and thats how to use them