**1. Homework Statement**

A motor is designed to operate on 117 V and draws a current of 12.2 A when it firsts starts up. At its normal operating speed, the motor draws a current of 2.30 A. Obtain (a) the resistance of the armature coil, (b) the back emf developed att normal speed and (c) the current drawn by the motor at one-third normal speed.

**2. Homework Equations**

[tex]I(t) = \frac{E}{R}(1-e^{-{\frac{R}{L}t}}) [/tex]

[tex]E= - N \frac{d \Phi }{dt} = -L \frac{dI}{dt}[/tex]

Where E = emf.

**3. The Attempt at a Solution**

So, what we at first thought for (a) was that normal speed is some sort of .. evening out or something similar to that, so we wanted to use Ohm's law to find the resistance (now looking at the numbers that's sort of absurd - how can I

_{max}be lower than the initial one? Doesn't really make sense), but obviously that's wrong, we realised when we came to (b). And we're stuck. We don't know how to proceed and for me it's a bit what's what? Is 12.2 the I

_{max}? Like, what does the question actually say?

**1. Homework Statement**

A generating station is producing 1.2 * 10

^{6}W of power that is to be sent to a small town located 7 km away. Each of the two wires that compromise the transmission line has a resistance per kilometre of length of 5.0 * 10

^{-2}Ohm/km. (a) Find the power used to heat the wires if the power is to be transmitted at 1200 V. (b) A 100: l [okay, so I'm not too sure about this last thing - it looks like it says this, but I can't be 100% sure, bad copy..] step-up transformer is used to raise the voltage before the power is transmitted. How much power is now used to heat the wires?

**2. Homework Equations**

**3. The Attempt at a Solution**

I need conceptual help here, first of all - this question is not from our textbook, but another one which my teacher has and our book apparently doesn't go through this enough, cos I'm so lost. I don't even really know which angle to approach the problem from. Hint in the right direction, anyone?