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unofficial astrophysics exam?? watch

1. hmm, although overall I thought it was a good paper
2. 9.4x10^-6 seems waaaay too big.
The whole visable spectrum is only about 300x10^-9m! (400-700nm)
3. (Original post by Phil23)
the usual stuff - scattering, scope can pick wavelengths that would be absorbed by earths surface, etc.
Good. that what I wrote about...
4. (Original post by Whatsername)
hmm, although overall I thought it was a good paper
Me too. Although alot of people would have run out of time or been unable to do the last 2 questions, which were much harder than the past papers. Hopefully this will bring the boundaries down.
5. (Original post by SinghFello)
9.4x10^-6 seems waaaay too big.
The whole visable spectrum is only about 300x10^-9m! (400-700nm)
think you misread the question on the paper - it said CHANGE in wavelength, therefore i suppose 9.4micro metres is viable - anyhow, is we were to show delta T is approx 300K and Weins law is lambdamax .T= 2.89 x10^-3, i dont see how it could be anything else? has to be something x 10^-6 at least,

Phil
6. Hmm...

Yes, they asked what the change in wavelength is, since the star was turning my orange from yellow. So I found the wavelengh at both temperatures, and then found the difference.

So original temp was 4500K?(i cant remember??!), and the new was 4500+328K

original wavelength = 2.898x10^-3/4500 = 644nm
new wavelength = 600nm

change = 44nm (or whatever it is for the correct temperatures)

Im not sure where you get the x10^-6?
7. (Original post by SinghFello)
Hmm...
Im not sure where you get the x10^-6?
lets forget about it ok - i'm started to get worried now
8. Can anyone remember the exact wording of the penultimate question?
9. (Original post by Phil23)
lets forget about it ok - i'm started to get worried now
At the end of the day we'll probably get at least a mark for rearranging the eqn and putting in one value. I think it was a common mistake to put T as the temperature difference so they might even give a mark if you calculated the value wrongly.

Failing that the grade boundary will be lower for astro. I don't know what it was like at your centre but the majority of people at mine didn’t finish.

Personally, I though the first 3/4 of the paper was good but the last two questions were a poor choice because they required so many calculations and use of the memory button; and required us to re-use values in the question.

If like 80%-90% of people did the last part wrong could they just delete it off the paper, and not mark it? My school is complaining to Edexcel anyway
10. They wouldn't delete it off the paper - a part of physics is being able to calculate, manipulate formulae etc.... I really don't think you can complain about the question, it was nothing different to what has been seen before in physics papers imo.
11. (Original post by Whatsername)
They wouldn't delete it off the paper - a part of physics is being able to calculate, manipulate formulae etc.... I really don't think you can complain about the question, it was nothing different to what has been seen before in physics papers imo.
I realise that. I was able to manipulate the formula and bung the numbers in but I did feel there was a little too much on the paper for all the calculations and using the converted values from the parts before.

I am hoping I'll still get marks for rearranging the eqn and calculating the two values for temperature. I only showed the T^4 and did the rest on the calculator and got 301K; so I imagine they'll mark me down for that.

On the last part I didn't realise weins law wouldn't work for T=300K; exam panic i guess, but hopefully the grade boundaries will be low, so I'll be alr8

I still felt that the paper was too long, I think if the last question was on then timing would have been better. It may have been better if Wein's law had not been a follow on question from before, but it is Edexcel after all.

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