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Physics 2002 sample paper answers

  • 31-03-2012 2:21pm
    #1
    Incompetent
    Registered Users, Registered Users 2 Posts: 442 ✭✭


    Just had a quick search around and couldn't find any solutions or anything. I'm just doing heat questions and not sure about this one.. It's not in my books.

    Mainly the problem is with microwave interference: How does this affect heating of food? Is it something to do with constructive interference increasing amplitude, which gives more heat? That's a pure guess. And why does a rotating turntable ensure uniform heating? (apart from the obvious non physic-like answers I'm thinking :rolleyes:)


Comments

  • #2
    Incompetent
    Registered Users, Registered Users 2 Posts: 442 ✭✭Incompetent


    Another heat question...

    I just did an experiment question on the specific latent heat of fusion of ice. I got 322518.56 J/kg but the marking scheme only gave it to 3.2x10^5. Was my answer worth full marks? I assume so...


  • #3
    Bears and Vodka
    Registered Users, Registered Users 2 Posts: 2,249 ✭✭✭Bears and Vodka


    Incompetent wrote: »
    I got 322518.56 J/kg but the marking scheme only gave it to 3.2x10^5. Was my answer worth full marks? I assume so...

    Yes, it's up to the examiner to work out what your answer is in scientific notation. However it's good practice to have it in scientific notation.


  • #4
    Outkast_IRE
    Registered Users, Registered Users 2 Posts: 7,516 ✭✭✭Outkast_IRE


    Incompetent wrote: »
    Another heat question...

    I just did an experiment question on the specific latent heat of fusion of ice. I got 322518.56 J/kg but the marking scheme only gave it to 3.2x10^5. Was my answer worth full marks? I assume so...
    you will notice most example papers will give the answers to just one or two decimal places and expect you to use the 10^x amount on your answer to bring it to the one or two decimal places at the very end.

    They are both right answers but in college etc its preferred if you bring the answer back to just one or two decimal places.


  • #5
    Incompetent
    Registered Users, Registered Users 2 Posts: 442 ✭✭Incompetent


    subz3r0 wrote: »
    Yes, it's up to the examiner to work out what your answer is in scientific notation. However it's good practice to have it in scientific notation.


    Ah ok good. I just think that's really simplifying it too much. I suppose I'll give both.


  • #6
    Wicklowleaid
    Registered Users, Registered Users 2 Posts: 126 ✭✭Wicklowleaid


    in the microwave oven what essentially is generated is a standing wave. So you have antinodes of high amplitude and nodes of no amplitude. The food thus will cook at the antinodes, the turntable moves the food through the antinodes so u don't end up with cold hot cold hot. :)


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