An electricity generator produces a constant AC power P P\,P at a voltage VVV.
In Scheme X, this electrical power is transmitted directly to a town via transmission cables of total resistance RRR.
In Scheme Y, an ideal step-up transformer with a turns ratio Np:Ns=1:80N_p : N_s = 1 : 80Np:Ns=1:80 is installed at the generator output to step up the voltage before transmission over the same cables.
What is the ratio of the power dissipated as heat in the transmission cables in Scheme Y to the power dissipated in Scheme X?
1.25×10−21.25 \times 10^{-2}1.25×10−2
1.56×10−41.56 \times 10^{-4}1.56×10−4
8.00×1018.00 \times 10^{1}8.00×101
6.40×1036.40 \times 10^{3}6.40×103