VCAA 2010 U4

[Sm1l3y]

Question 12 makes absolutely no sense to me, it asks about power output, with a W in the box, but the answer says 240V.

SOOO lost?

Also, just a few quick question. What is used in DC generator and AC generator circuit? As in the CRO is used in DC, or something like that? And can you say that split rings are used in AC generators as a means of switching the AC to DC current?

I had a another one, but forgot it.

Thanks.

[Vincezor]

Question 12 makes absolutely no sense to me, it asks about power output, with a W in the box, but the answer says 240V.

Isn't it just a simple:







P = 1200W?

Also, just a few quick question. What is used in DC generator and AC generator circuit? As in the CRO is used in DC, or something like that? And can you say that split rings are used in AC generators as a means of switching the AC to DC current?

Don't AC generators use slip rings though? :S

I would think any load connected to the slip rings/split rings can be used to complete the circuit... However I may be wrong, :S

[Sm1l3y]

I did the exact same thing, but the answer says 240V, I got no idea?

At Jack's he was saying that the split rings used in an AC generator changes it to DC power?

[Lasercookie]

A motor generates AC power. Pretty evident if you think about how the flux changes.
A split ring commutator doesn't transfer out the negative phase to the external circuit. So you get a DC generator.
A slip ring doesn't mess with it, it just connects the motor to the external connection. So you get an AC alternator.

If you're having trouble deriving the working out from the Assessor Reports, use iTute's solutions for VCAA exams. They show the exact working out. The assessor reports are still good though, but often they're full of other comments which can make the answer ambiguous (like for question 12, you didn't read the assessor report carefully enough )

[paulsterio]

I find these solutions also very good:
http://www.vicphysics.org/examsolutions.html

- Better than iTute in my opinion

But make sure you read the Assessor's Report - they give you a lot of tips and do's/don't's plus there's plenty of information on exam technique...etc in there!

[Lasercookie]

Also a CRO is an oscilloscope. It has no effect on the actual operation, it's just a tool that shows what the waveform looks like. Kind of like how an ammeter will show you what the current is. Sticking in the ammeter (assume that it is ideal) won't have any effect on the actual circuit or resistance.

[HarveyD]

when do you guys reckon is the best time to do the VCAA exams?

[Lasercookie]

when do you guys reckon is the best time to do the VCAA exams?

Others will probably differ from my opinion.

I started off with VCAA 2010. I've also done VCAA 2007 and 2009.

I'll do the other VCAA exams in the next two weeks (2002 onwards). Main reason for this is because I find them to be a more enjoyable experience than other trial exams. The questions are pretty well written and the solutions are correct unlike a few other companies...

I'll also redo some of them (and look over all of them thoroughly at the very least) the days before the exam.

[HarveyD]

ah okay
howd you go on the exams?

[Lasercookie]

ah okay
howd you go on the exams?

I've been getting about the B+/A range. Still a lot of room for improvement. I'm finishing with about 15 to 30 minutes to spare, so I'm pretty happy with that - leaves more than ample time for checking over.