(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

3. A 15MeV Alpha particle is incident at impact paramter b=0 on a Mg Nucleus, atomic number Z=12 and atomic mass A=24. What is the distance of closest approach?

2. Relevant equations

None given, but I thought the following might be relevant:

[tex]r_{min}=\frac{Zke^{2}}{KE}[/tex]

[tex]b=\frac{Zke^{2}}{KE} * \sqrt{\frac{1+cos\theta}{1-cos\theta}} [/tex]

3. The attempt at a solution

First I thought that given the above:

[tex]b=r * \sqrt{\frac{1+cos\theta}{1-cos\theta}} [/tex]

[tex]0=r * \sqrt{\frac{1+cos\theta}{1-cos\theta}} [/tex]

[tex]r=0 [/tex]

But then I thought perhaps the distance of closest approach is just the radius of the nucleus:

[tex]r=r_{0}A^{1/3} [/tex]

Now I'm confused about which is appropriate!

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# Homework Help: Impact Parameter, Closest Approach

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