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stripes
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Homework Statement
For alpha particles of 7.7 MeV, what impact parameter will result in a deflection of 2 degrees for a thin gold foil?
Homework Equations
impact parameter equation, [tex]b=\frac{kq_{\alpha}Q}{m_{\alpha}v^{2}}cot\frac{\theta}{2}[/tex]
The Attempt at a Solution
Pretty easy, just plug and play into[tex]b=\frac{kq_{\alpha}Q}{m_{\alpha}v^{2}}cot\frac{\theta}{2}[/tex], but my textbook and instructor aren't very specific with what numbers we put in exactly. We know that mv^2 = 2KE, but as for the k, q and Q, do I just put k = 8.988x10^9, q(alpha) = 2(1.6x10^-19) and Q = 79(1.6x10^-19)?
I plugged in all of these numbers, along with theta = 2 degrees, and I get b = 2.70x10^-31 m. That seems kind of small for a deflection of 2 degrees. Did I do something wrong? Am I plugging in the wrong numbers?
Thank you all in advance.