Physics (Electrostatic) question !?

Question

I'm stuck at one questions.

Explain why electric energy is transmitted at high potential and how efficiency affects power consumption (how does htis affect our society?)

Thank you !

Answer 1

Transmission is at high voltage to minimize resistive power losses. In a wire of resistance R, the resistive power loss Wl = I^2*R (not I*R^2 per 1st answer; Wl = voltage drop in wire * current = dE*I = (I*R)*I). So to minimize Wl at a given power W, you can decrease R (use fatter wire, expensive) or decrease I (easier, because W=E*I, voltage * current, so just increase E to compensate).
How efficiency affects power consumption, and its effect on society, aren't physics questions, but I'd guess that most people are indifferent about the efficiency with which power reaches them, and those who do care are more concerned with what they can control, i.e., the efficiency of their own use of power.

Answer 2

You may remember that losses in a conductor are determined by IR^2 (current x resistance squared). So we wish to transmit power with the lowest possible current. Power = current x voltage. So we step up voltage to transmit power and step it down (with transformers on the utility poles, for example) to use it.

This is why we use alternating current -- it can be stepped up/down with transformers. As Edison noted, direct current is much safer than alternating current. (In most electrocutions, it's not the energy, but the information that kills! The heart and the brain don't work at 60 Hz!)

But direct current cannot be (easily) stepped up for transmission. (I have neglected some subtleties, like power factors, phase angles, radiative losses and so forth...)

Answer 3

properly, in case you do not get this then i elect to advise going to workplace hours. That being suggested, use F=(Gm_1m_2)/r^2. G is a relentless so which you will seem it up on your e book. quite for a and b you purely could desire to plug in numbers. the gap between the two mass is r. For c, use c^2=a^2+b^2 to locate the gap between the a lot. considering's a ninety degree triangle, you need to use it to locate the ensuing c. Then like a and b, plug it in.