changes made:
1 added \Omega to symbol Omega
2 reorganize the objects into groups for ease of sharing

reference:
Electric cable power loss

Aborb Physics by David Fairhurst free to use on their website only so not embedded here  http://www.absorblearning.com/media/item.action?quick=7v
Transformers and Long-Distance Power Transmission  by Michael Richmond. This work is licensed under Attribution-Noncommercial-Share Alike 2.0 Generic http://spiff.rit.edu/classes/phys213/lectures/transform/transform.html so i am going to share remixed and sharealike so copyright resepcted!