Edexcel Physics (IAL) Unit 5 : Physics from Creation to Collapse - 18th June 2015

Hi guys
I didn't find any other threads on the ial paper so I created that one, little bit worried of unit 5 especially after that easy unit 4

So how is revision going on so far ?

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Reply 1

Sal296

A pan contains water at a temperature of 300 K. The water temperature is increased to330 K. Assuming that the pan behaves like a black body, the rate at which energy isemitted as radiation from the pan changes by a factor of
A 0.9B 1.1C 1.2D 1.5

Why is it D, can someone explain?

Reply 2

pastaisfantastic

Original post by Sal296

It says the pan behaves like a black body, so it must obey the equation L=σT^4A.
The rate at which energy is emitted from the pan is luminosity, which is represented in the equation by L. If we rearrange, we can get that L/(T^4)=σA
σA is the same for both situations, because the area of the pan doesn't change and σ is a constant. So:

(initial L) / (inital T^4) = (new value of L) / (new value of T^4)

The factor by which the luminosity changes (which is what the question is asking for) is the new luminosity divided by the initial luminosity. We rearrange the equation to give:

factor by which luminosity changes= (new value of T^4) / (initial value of T^4)

so substitute in your values for T to get (330)^4 / (300)^4 which is equal to 1.46
This rounds up to give you 1.5, which is the correct answer.
Hope this helps :smile:

Reply 3

Ambrina

I think there are going to be confusing graph questions. Wien's law or oscillations graphs

Reply 4

Fatima SJ

Can someone tell how to calculate the logarithmic scale for Hertzsprung-Russell (H-R) Diagram? This is a frequent question.

Reply 5

D3M9

So how was the paper??

Reply 6

Fatima SJ

Original post by D3M9

So how was the paper??

It was okay-ish
what was the answer for the first 3 MCQS?

Reply 7

D3M9

Original post by Fatima SJ

It was okay-ish
what was the answer for the first 3 MCQS?

The paper was weird!!! I chose C for the first and high-high-sumthin for the second and third i dont remember. I may be completely wrong though!! :smile:

Reply 8

Fatima SJ

Original post by D3M9

The paper was weird!!! I chose C for the first and high-high-sumthin for the second and third i dont remember. I may be completely wrong though!! :smile:

i hope the grade boundaries arent too high

Reply 9

Einstein2015

Multiple choice (correct me please)
1D
2B
3B
4A
5C
6A
7A
8C
9B
10D

Reply 10

ME ^^

i felt the paper was weird :/ there where such less calculations n more of theory answers:/
i wish gbs r low:')

Reply 11

D3M9

Original post by Fatima SJ

i hope the grade boundaries arent too high

Yea!! I pray the grade boundaries aren't tooo high. Although honestly I was expecting an extremely tough paper not a weird one :P

Reply 12

ozbilege

I was also expecting a tough paper with weird equation derivations and weird concepts... the concepts were easy, what they did with the questions were not. I'm hoping for low boundaries so I can get my A* overall with an A from this unit.

Reply 13

Jasmine:))))

What's your velocity calculated in the last question?
Mine is 2.02ms^-1
and do you guys have sth like 1.8 x 10^41 kg?

Reply 14

iWant.A

Original post by Jasmine:))))

What's your velocity calculated in the last question?
Mine is 2.02ms^-1
and do you guys have sth like 1.8 x 10^41 kg?

For the velocity, i have found from before the frequency which was 1.01 Hz and then i used Vo=ωXo and I calculated 1.40 ms^-1 as the maximum velocity.

I have also stated that it occurs in equilibrium position

Reply 15

Jasmine:))))

Original post by iWant.A

Wasn't the frequency 1.06/1.07Hz?
I calculated by 9.81=W^2 X A
W=2(pi)f
so that f=1.1Hz(2 s.f.)

and I simply calculated the velocity by mgh=0.5mv^2

This paper is the weirdest one. Unlike all the past papers.

Reply 16

iWant.A

Original post by Jasmine:))))

I really dont know, I think it was weird but do-able

Reply 17

Jasmine:))))

Original post by iWant.A

I really dont know, I think it was weird but do-able

I think your answer for velocity is correct.
I wasn't sure for many answers in this paper. When I was doing the past papers, I was quite confident on the answers.
Just hope for a low boundary. :frown: