Join TSR now and get all your revision questions answeredSign up now

AQA Physics PHYA5 - Thursday 18th June 2015 [Exam Discussion Thread] Watch

    • Thread Starter
    Offline

    3
    ReputationRep:
    (Original post by Mehrdad jafari)
    It's june 2002 paper, as it's written in the web link


    Posted from TSR Mobile
    I see!

    (Original post by gcsestuff)
    Thanks makes sense! Another good case of not reading the question properly. And unit 4 in the old syllabus included nuclear energy, some quite good questions in there


    Posted from TSR Mobile
    Thanks man - would you mind linking me to that website? Might have a go at a few.


    Posted from TSR Mobile
    Offline

    2
    ReputationRep:
    (Original post by frankiejayx)
    Would anyone mind explaining the concept of critical mass to me? For the fuel rods
    It's the minimum amount of mass required for fission to keep occurring, I think it's something to do with the proportion of neutrons on the surface, if you're left with too few the nuclei aren't heavy enough to split. I think I'm right but I'm not 100% either. I'll take a photo of my old text book when I'm home


    Posted from TSR Mobile
    Offline

    2
    ReputationRep:
    (Original post by CD223)
    I see!



    Thanks man - would you mind linking me to that website? Might have a go at a few.


    Posted from TSR Mobile
    Just google tom Reds blog. He has all the old papers for all units. He has a navigation bar at the top of his page.


    Posted from TSR Mobile
    • Thread Starter
    Offline

    3
    ReputationRep:
    (Original post by frankiejayx)
    Would anyone mind explaining the concept of critical mass to me? For the fuel rods
    Critical mass is the mass of fuel needed for a chain reaction to occur. In other words, the mass required for one neutron released from each fission event to cause at least one other fission reaction.

    Below the critical mass, on average one fission event causes less than one more fission event (sounds stupid but if you imagine a large quantity of atoms it makes more sense).

    At the critical mass, one fission event can lead to just one other fission event.

    Above the critical mass, one fission event can go on to cause several more fission events.


    Posted from TSR Mobile
    • Thread Starter
    Offline

    3
    ReputationRep:
    (Original post by gcsestuff)
    Just google tom Reds blog. He has all the old papers for all units. He has a navigation bar at the top of his page.


    Posted from TSR Mobile
    Brilliant thanks


    Posted from TSR Mobile
    Offline

    2
    ReputationRep:
    (Original post by gcsestuff)
    It's the minimum amount of mass required for fission to keep occurring, I think it's something to do with the proportion of neutrons on the surface, if you're left with too few the nuclei aren't heavy enough to split. I think I'm right but I'm not 100% either. I'll take a photo of my old text book when I'm home


    Posted from TSR Mobile
    Okay Thank you
    Offline

    2
    ReputationRep:
    (Original post by CD223)
    Critical mass is the mass of fuel needed for a chain reaction to occur. In other words, the mass required for one neutron released from each fission event to cause at least one other fission reaction.

    Below the critical mass, on average one fission event causes less than one more fission event (sounds stupid but if you imagine a large quantity of atoms it makes more sense).

    At the critical mass, one fission event can lead to just one other fission event.

    Above the critical mass, one fission event can go on to cause several more fission events.


    Posted from TSR Mobile
    Thanks!
    • Thread Starter
    Offline

    3
    ReputationRep:
    (Original post by frankiejayx)
    Thanks!
    No problem


    Posted from TSR Mobile
    Offline

    2
    ReputationRep:
    (Original post by CD223)
    No problem


    Posted from TSR Mobile
    https://m.youtube.com/watch?v=T5qmCkSU7CU

    I watched this set of videos, I thought he was quite good


    Posted from TSR Mobile
    • Thread Starter
    Offline

    3
    ReputationRep:
    (Original post by gcsestuff)
    https://m.youtube.com/watch?v=T5qmCkSU7CU

    I watched this set of videos, I thought he was quite good


    Posted from TSR Mobile
    Ah that's cool
    Offline

    19
    ReputationRep:
    are we expected to be able to derive the equations for the ideal gas laws and kinetic theory?
    Offline

    1
    ReputationRep:
    Hi does anyone know why there are no PHYA5 papers for the January set of papers in all the years on the AQA website? Theres papers for PHYA4 for Jan and June but for PHYA5 its only June?
    Offline

    2
    ReputationRep:
    I don't get why they did  mc(30 - T_f) on the mark scheme. I get why they did mc(T_f - 3) As that's the difference between before and after temperature? At least I think.


    Offline

    10
    ReputationRep:
    (Original post by Master Sam)
    Hi does anyone know why there are no PHYA5 papers for the January set of papers in all the years on the AQA website? Theres papers for PHYA4 for Jan and June but for PHYA5 its only June?
    PHYA5 papers were only sat in summer, because it's the second unit of the year the idea was do phya4 for january then do phya5 for june :/ it's a pain now when we've hardly got any past papers!
    • Thread Starter
    Offline

    3
    ReputationRep:
    (Original post by AR_95)
    are we expected to be able to derive the equations for the ideal gas laws and kinetic theory?
    Yes, it's in the spec.


    Posted from TSR Mobile
    • Thread Starter
    Offline

    3
    ReputationRep:
    (Original post by dominicwild)
    I don't get why they did  mc(30 - T_f) on the mark scheme. I get why they did mc(T_f - 3) As that's the difference between before and after temperature? At least I think.


    In thermal equilibrium the cola reaches the same final temperature as the glass.

    In other words, the rise in thermal energy of the cola equals the fall in thermal energy of the glass.

    There is no net transfer of thermal energy beyond this point.

    Rise in thermal energy of the cola as it warms up from 3.0 degrees Celsius to the final temperature:
    

{\Delta Q_{Cola}} = {m_{Cola}} {c_{Cola}} (T_f - 3)

    Loss of thermal energy of the glass as it cools from 30 degrees Celsius to the final temperature:
    

{\Delta Q_{Glass}} = {m_{Glass}} {c_{Glass}} (30 - T_f)

    Equating the two, as they're in thermal equilibrium gives:

    

0.250 \times 840 \times (T_f - 3) = 0.200 \times 4190 \times (30 - T_f)

    

\therefore T_f = 8.41 C^{o}


    Posted from TSR Mobile
    Offline

    2
    ReputationRep:
    What is smiley face meant to be???

    Posted from TSR Mobile
    • Thread Starter
    Offline

    3
    ReputationRep:
    (Original post by a.a.k)
    What is smiley face meant to be???

    Posted from TSR Mobile
    Huh? :L


    Posted from TSR Mobile
    Offline

    2
    ReputationRep:
    I am seeing smiley face between questions and answers. Is it just me.

    Posted from TSR Mobile
    • Thread Starter
    Offline

    3
    ReputationRep:
    (Original post by a.a.k)
    I am seeing smiley face between questions and answers. Is it just me.

    Posted from TSR Mobile
    Probably - not quite sure where you're seeing them


    Posted from TSR Mobile
 
 
 
Poll
Which Fantasy Franchise is the best?

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Quick reply
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.