Consider a
device R, to which a power P is to be delivered via transmission cables
having a resistance Rc to be dissipated by it finally If V is the voltage
across R and I the current through it, then
P = V I
(3 34)
The connecting wires from the power station to the device has a finite
resistance Rc The power dissipated in the connecting wires, which is
wasted is Pc  with
Pc = I 2 Rc
   
2
2
c
P R
V
=
(3