OCR Gateway Physics P4P5P6 - 18/06/13

I think you have to do an A2 FM module. so either FP2, FP3 or FP4. So none of them are compulsory but you must do one in your A2 modules.

Even though I used both current and number of turns calculations, I think current is the one they're looking for. The question started with an example of her phone charger - if they really wanted us to work out the number of turns - they would want us to work out the exact number of turns, not just how many times more turns there were.

They probably wanted you to say something along the lines of "less turns on the secondary coil" without the need of calculation, and then explained how it was possible for voltage to drop, because this is made up by the fact that current increases (then give the current calculation), so there is no actual loss of energy. That's how you use current to answer the question - the only way voltage can be stepped down without energy loss (conservation of energy) is if current was increased to compensate for the drop in voltage.

Edit: Also some phone chargers can only work at a high enough current - so you could say that current increasing allows the charger to work.

edexcel ..dont have fp4 ... it might be different for different exam boards
i want to do all 18 .. but i dont think it will happen

There's an infinite range of "exact number of turns" - as long as it fits the 46:1 ratio it's fine, so I said there would be 46 more turns and as an example said the primary coil would have 46 turns and the secondary would have 1 (which fits the ratio).

The question was literally nothing to do with conservation of energy. That won't answer the "how does it work?" part. That would be something along the lines of "why does the current change?". You should have talked about the primary coil producing a constantly changing magnetic field which causes electromagnetic induction in the secondary coil.

Ah I'm AQA. I think 18 will be too much work and you'd be better off going for 100 UMS in 12 but by all means go for it if you think you can do it.

I personally feel that its easier to do 15/18 at a solid A...rathe than 12 100s..but im only comparing 3 modules ive done an the 2 I self taught since jan.....

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If you are so convinced it was asking for number of turns, not current, then find me a past paper question that asks for number of turns, but not an exact answer.

No. I'm perfectly content in my mind that working out the number of turns is a viable calculation which answers the "how would it be constructed" aspect and that working out the current is relatively irrelevant. Having you know that or not does not affect me.

You didn't mention the catalyst :P But that seems like you should get full marks
That said...maybe those could be classed as 1 point? Not sure though :/

How did you find the exam?


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Any of you self teaching AS Chem/Physics/Maths over the summer? I thought if we have a few people we could set up a thread to discuss and help each other.

Any of you self teaching AS Chem/Physics/Maths over the summer? I thought if we have a few people we could set up a thread to discuss and help each other.

Yes I am. Great idea. I skimmed through my chemistry and physics AS revision guides earlier - the content is fascinating.

Can you set it up in the appropriate section and post the link here?

Any of you self teaching AS Chem/Physics/Maths over the summer? I thought if we have a few people we could set up a thread to discuss and help each other.

Hmmm...I might do this but I'm going on holiday for a while so may do so when I get back...



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Okay this is the only post that has given me some inkling of hope D: That was a bloody nightmare of an exam, I nearly had a panic attack

Dont worry - I did 3 mocks before the exam and got straight As almost A*s in all 3 but I still came out of that exam hall with tears in my eyes. It's so dissapointing after putting so much work into it - makes it feel pointless and then there the education people are saying that GCSEs are too easy. I don't think they'll understand until they have to spend 3 weeks waking up at 6.30 to start revising for a subject that your not the slightest bit interested in and only stop revision for it at 9.00 at night -___- drives me insane... Hope everyone has done well in everything and have a fab summer xxx