Hey! Sign in to get help with your study questionsNew here? Join for free to post

Unit 5 Nuclear question (June 2011)

Announcements Posted on
Win top prizes...including a cool £10k. Check TSR's competition page 19-05-2016
  1. Offline

    I'm a little bit confused by one of the questions. It is scoring marks for something which it doesn't appear to be asking for.

    It's AQA Unit 5 June 2011 Question 2b.

    "For the reaction to take place the a particle must come within a distance, d, from
    the centre of the aluminium nucleus.
    Calculate d if the nuclear reaction occurs when the a particle is given an initial
    kinetic energy of at least 2.18 × 10–12 J."

    The question then suggests that I use (Q1.Q2)/(4.pi.Eo.r) as the energy.

    So I rearrange the equation to move the provided kinetic energy to the bottom of the equation, and bring the radius up as the subject in order to calculate it. I get the correct answer, which is about 2.75e-15 metres.

    However, calculating that is just worth 2 of the 3 points. There is a further point in the mark scheme for writing:

    "kinetic energy lost by the α particle approaching the nucleus is equal to the potential energy gain"

    I'm really lost as to why they want me to state that. Do I lose the mark for not writing that? I achieved all the other marks for that question. I have the mark for using the correct equation in the right way. Does that provide a mathemetical equivalent to writing down the worded answer?

    Link to question paper
    Link to answer paper

    Have I missed something from this question or what?

  2. Offline

    i dont think so, i was actually doing this question like 3 hours ago funnily enough!
    basically as long as you show that potential=kinetic in your workings directly or indirectly you get the mark, you wouldnt have to put it in words and all that


Submit reply


Thanks for posting! You just need to create an account in order to submit the post
  1. this can't be left blank
    that username has been taken, please choose another Forgotten your password?
  2. this can't be left blank
    this email is already registered. Forgotten your password?
  3. this can't be left blank

    6 characters or longer with both numbers and letters is safer

  4. this can't be left empty
    your full birthday is required
  1. Oops, you need to agree to our Ts&Cs to register
  2. Slide to join now Processing…

Updated: June 14, 2012
TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

Today on TSR

Edexcel GCSE maths answers

Check the unofficial mark scheme

What date is the EU referendum on?
Quick reply
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.