Help, i&#x27;m about to cry!!!! Who&#x27;s done astronomy gcse?

How did everyone find the exam today???

Reply 5

lilacpotato

12

Original post by beccadf1

How did everyone find the exam today???

I thought was a pretty harsh paper, what about you?

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Reply 6

lilacpotato

12

Original post by beccadf1

How did everyone find the exam today???

I thought it was a pretty harsh paper, what about you?

Posted from TSR Mobile

Reply 7

I agree, it was very harsh. It was nothing like any of the past papers and most of the questions heavily relied on you applying your knowledge. What did you put for the size of the planet question?

Reply 8

Selena22

3

does anyone have an idea of what the grade boundaries will be like? It was so hard!

Reply 9

lilacpotato

12

Original post by beccadf1

I agree, it was very harsh. It was nothing like any of the past papers and most of the questions heavily relied on you applying your knowledge. What did you put for the size of the planet question?

Omg I was so confused! I think I ended up working out the size of the star instead! :biggrin:

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Reply 10

The grade boundaries are only made after the exams have been marked but here are last years boundaries:
a* - 98
a - 85
b - 72
c - 59
d - 52
e - 45
f - 39
g -33

Hopefully they will be quite lenient with the grade boundaries considering how hard it was!

Reply 11

Original post by lilacpotato

Omg I was so confused! I think I ended up working out the size of the star instead! :biggrin:

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I put 900,000 km but i think you had to do something else as well to get 2 marks (seeing as this only dimmed the brightness by 50%)

Reply 12

KiraTheSaviour

Original post by beccadf1

I put 900,000 km but i think you had to do something else as well to get 2 marks (seeing as this only dimmed the brightness by 50%)

What you've done is calculated the distance the planet traversed, while blocking the star's light.

If the brightness really did dim by 50%, then:
900,000/4 = 225,000 to get the radius
225,000^2 x π =

159,038,437,500km^2
area of the visible face of the planet
Not realistic at all.
So we come to the conclusion that we need to use the 6 hour long dip in brightness and the speed of the planet to work this out.
I have no idea.. Did I misinterpret/misread the question??

Reply 13

Ona2000

2

I tried doing this thing you know how there is like a slow decrease as like the edge of the planet comes on and then it plateaus to a constant luminosity I took that time that that took and then used the values of the speed to work out how big it was😬 I'm not explaining it well but that's what I tried

Reply 14

Original post by KiraTheSaviour

What you've done is calculated the distance the planet traversed, while blocking the star's light.

If the brightness really did dim by 50%, then:
900,000/4 = 225,000 to get the radius
225,000^2 x π =

159,038,437,500km^2
area of the visible face of the planet
Not realistic at all.
So we come to the conclusion that we need to use the 6 hour long dip in brightness and the speed of the planet to work this out.
I have no idea.. Did I misinterpret/misread the question??

No it was much easier than that. It takes 6 hours to orbit the star at 150000km/h. Therefore the diameter of the star is 9000000km. Since it takes away 50% of the light, then the planet must cover up 50% of the star so it is 4500000km in diameter.

Reply 15

Original post by Ona2000

I tried doing this thing you know how there is like a slow decrease as like the edge of the planet comes on and then it plateaus to a constant luminosity I took that time that that took and then used the values of the speed to work out how big it was😬 I'm not explaining it well but that's what I tried

Yeah, usually the dip in the light curve is curved not flat like it was here because it's a gradual process, but I guess you just had to work with the information it gave you.i thought it was weird though. Definitely a nasty question

Reply 16

ThomasRules

7

Original post by Andreahdlfuente

Yeah, usually the dip in the light curve is curved not flat like it was here because it's a gradual process, but I guess you just had to work with the information it gave you.i thought it was weird though. Definitely a nasty question

That graph was horrible - it took twice as much time to go off the star as it did to go onto it. I got 112 500km (from the time it took to get on and off and then an average)

Reply 17

Original post by ThomasRules

That graph was horrible - it took twice as much time to go off the star as it did to go onto it. I got 112 500km (from the time it took to get on and off and then an average)

Ikr. I thought about doing something like that but then again it was only worth 2 marks, so I thought that that was too complicated.

Reply 18

ThomasRules

7

Original post by Andreahdlfuente

Ikr. I thought about doing something like that but then again it was only worth 2 marks, so I thought that that was too complicated.

Its a minute per mark though, and you can do about 5 of those multi choice questions in a minute

Reply 19