Re: Yr 12 physic help!!
I don't know about question 1, but here's my attempts at question 2 and 3.
2) Explain how transmission line are:
- insulated from supporting structures.
Transmission lines generally carry high amounts of voltage, and since metallic structures are cheaper than timber ones, we must insulate the transmission lines and its' supporting structure.
If you have a look carefully next time you see a transmission line structure, you will notice the circular disks that are on the arms of the metallic arms that hold the cables.
These circular disks are in fact ceramic disks, and since ceramic is an absolute insulator, it prevents electricity from jumping from the transmission line to the metallic structure (however this does not apply on moist / humid days, as electricity jumps longer distances with the presence of water molecules).
- protected from lighting strikes.
All (or most) transmission line carrying structure has an extra wire. This extra wire is placed on the peak of the structure, and connects with every peak of the next structure. At the end of the wire, it is guided into earth, hence the name earth wire.
When the lightning strikes the peak of the structure, the electricity is passed on into the earth wire, and is safely guided to the ground.
The presence of an earth wire prevents an excess surge of electricity passing through transmission wires.
3) Analyze secondary information on the competition between Westinghouse and Edison to supply electricity to cities.
I believe there is an abundance of topics relating to Westinghouse vs Edison on the forums.
Here's one:
http://community.boredofstudies.org/264/motors-generators/16970/westinghouse-vs-edison.html
Basically, you need to outline the methods which Westinghouse and Edison used to convince the general public that their type of electricity (AC vs DC, respectively) was better.
This is generally the history part of Motors and Generators, so all the work in this dot point is theory.
Good luck!
- P!xel
