Edexcel IAL phy unit 5 18th June 2015 discussion

Fatima SJ

3

Hello. How was it?
what was the answer for the first 3 MCQs?

Reply 1

Undisclosed 15

18

Original post by Fatima SJ

Hello. How was it?
what was the answer for the first 3 MCQs?

The answer for the energy and frequency question is low energy and low frequency. Not sure what the other 2 were

For the 2nd last part of the last question were amplitude increased as the girl bent her knees, was the effect resonance?

The paper was ok overall. I would have preferred more astrophysics questions.

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Reply 2

Fatima SJ

OP

3

Original post by Undisclosed 15

The answer for the energy and frequency question is low energy and low frequency. Not sure what the other 2 were

For the 2nd last part of the last question were amplitude increased as the girl bent her knees, was the effect resonance?

The paper was ok overall. I would have preferred more astrophysics questions.

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That was what i wrote. Because i couldnt think of anything else
what bout the main sequence star mcq? and How did hubble measure distances to gaalxies?

One more thing the question about Sun . the last part where they asked what scientists think about the stars that have same speed as the sun?

Reply 3

Lallana 11

2

Trigonometric parallax cuz it was nearby stars , not far away

Reply 4

Undisclosed 15

18

I didn't know the main sequence question.

I just realised for the beta decay question I put the numbers the wrong way around for the beta particle. Will I still get one mark though because each particle is conserved? Such a stupid error.

Also, how did you find power radiated per m squared?

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Reply 5

Fatima SJ

OP

3

Original post by Lallana 11

Trigonometric parallax cuz it was nearby stars , not far away

But they were talking bout galaxies :| Is it the same thing?

Reply 6

Fatima SJ

OP

3

Original post by Undisclosed 15

I didn't know the main sequence question.

I just realised for the beta decay question I put the numbers the wrong way around for the beta particle. Will I still get one mark though because each particle is conserved? Such a stupid error.

Also, how did you find power radiated per m squared?

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If that question was two marks then you'll get a mark bt if it was just one mark then maybe not

I just took A as 1 because it was per m2

Reply 7

rachu

8

Original post by Fatima SJ

But they were talking bout galaxies :| Is it the same thing?

I dint think it is parallax.. it might be cephid
I wrote radio waves because of his radio telescope but might be wrong.
For HR it was low low low i think .. and what did you get for ke or air molecules?

Reply 8

Fatima SJ

OP

3

Original post by rachu

I dint think it is parallax.. it might be cephid
I wrote radio waves because of his radio telescope but might be wrong.
For HR it was low low low i think .. and what did you get for ke or air molecules?

are you sure it was low low low? What was your answer to the mars question bout the change in gpe?
We had to equate KE to 3/2 kT and calculate.
What was your answer to the last question of the last part. Why is the oscillation not SHM?

Reply 9

Undisclosed 15

18

Original post by Fatima SJ

If that question was two marks then you'll get a mark bt if it was just one mark then maybe not

I just took A as 1 because it was per m2

Ye it was 2 marks

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Reply 10

Fatima SJ

OP

3

Original post by Undisclosed 15

Ye it was 2 marks

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Then i guess you'll get one mark

Reply 11

kor97

1

Original post by Fatima SJ

are you sure it was low low low? What was your answer to the mars question bout the change in gpe?
We had to equate KE to 3/2 kT and calculate.
What was your answer to the last question of the last part. Why is the oscillation not SHM?

For the Mars mcq, I got -1.2%.
It was 3 marks so I think you had to say the conditions for SHM and also that acceleration is not proportional to displacement when she's in the air (it's 9.81).

Reply 12

sj97

3

Original post by kor97

For the Mars mcq, I got -1.2%.
It was 3 marks so I think you had to say the conditions for SHM and also that acceleration is not proportional to displacement when she's in the air (it's 9.81).

What did you get for the milky way question?

Reply 13

kor97

1

Original post by sj97

What did you get for the milky way question?

which bit?
also can someone make a chatzy?

Reply 14

sj97

3

Original post by kor97

which bit?
also can someone make a chatzy?

the mass and the explaining 2 markers.
for the mas i got something x 10^41, and then for the first part i talked about the momentum proportions and all that and i wasn't too sure on the second bit o i mentioned something about red shift and receding and all that.

Reply 15

sj97

3

Original post by Fatima SJ

are you sure it was low low low? What was your answer to the mars question bout the change in gpe?
We had to equate KE to 3/2 kT and calculate.
What was your answer to the last question of the last part. Why is the oscillation not SHM?

Don't forget that you then had to multiply the 3/2kt by the total number of molecules! This question came up on a past paper :smile:

Reply 16

kor97

1

Original post by sj97

the mass and the explaining 2 markers.
for the mas i got something x 10^41, and then for the first part i talked about the momentum proportions and all that and i wasn't too sure on the second bit o i mentioned something about red shift and receding and all that.

Yes I remember the question now. I got x10^41 as well. I talked about the gravitational field strength decreasing and centripetal force decreasing so v decreases (rearranged equations and explained it with those). I luckily happened to read something about that before so I knew it was something to do with dark matter. I'm not sure if I explained it well enough to get the marks.
http://ircamera.as.arizona.edu/NatSci102/NatSci102/lectures/darkmatter.htm
That sort of explains it.