Power loss in transmission lines (Electromagnetic Induction and Faraday's Law)

[confusedbyphysics]

Show that the power loss in transmission lines, PL, is given by PL = (PT)^2 X R/(V^2), where PT is the power trasmitted to the user, V is the delivered voltage, and R is the resistance to the power lines.

I don't even know where to start. I am so confused by this chapter, I don't know what this question has to do with magnetic flux and Lenz's law and the other stuff in the chapter. Any help please??

 

[nrqed]

Show that the power loss in transmission lines, PL, is given by PL = (PT)^2 X R/(V^2), where PT is the power trasmitted to the user, V is the delivered voltage, and R is the resistance to the power lines.

I don't even know where to start. I am so confused by this chapter, I don't know what this question has to do with magnetic flux and Lenz's law and the other stuff in the chapter. Any help please??

It has nothing to do with Lenz law or flux, indeed.

Think of a simple circuit with two resistors (representing the resistance of the line and the resistance of the load (where the user is drawing power from).

You have P_L = R_1 I^2 and P_T = R_2 I^2 where R_1 is the resistance of the lines. You also have V = R_2 I where V is the voltage delivered to the user. Use the last two equations to isolate I and plug in the first and you will get the answer. (also, you could use directly P_T = V I which gets you to the answer faster).

Pat