1. The problem statement, all variables and given/known data Electricity generated in the power station is stepped up by a transformer X from 25kV to 400kV before transmitted by overhead cable. Then it is stepped down to 200V through another transformer Y before entering domestic circuits. Assume all transformers are ideal. Given the power transmitted through the cables and the total resistance of the cables is 4x10^3 kW and 1Kohm respectively. Find (I) the electricity is not stepped up by X (3marks) (II) the electricity is stepped up by X (2 marks) 2. Relevant equations Ip / Is = Ns / Np 3. The attempt at a solution In (I),I tried to find out the power lost in the cable by finding the current in the transmitting cable by 4 x 10^3 x 1000 /25000 x (25 /400)=10A, Power=10^2 x 1000 = 100000W, I thought it was the electricity NOT stepped up by X, but the answer turned out to be 100000W is the electricity stepped up by X(the answer of (II)). I don't understand what does the question mean.