Finding the potential difference of an alpha particle.

AI Thread Summary
To determine the potential difference needed to accelerate an alpha particle to reach a uranium nucleus, the relationship between kinetic energy (KE) and potential difference (ΔV) is crucial. The equations KE = qΔV and conservation of energy principles are applied, but the discussion highlights confusion over unknown variables in the equations. It is clarified that while the alpha particle's kinetic energy is zero at the nucleus's surface, potential energy remains significant. The key takeaway is that the charge of the alpha particle can be used to calculate the necessary ΔV to achieve the required kinetic energy for reaching the nucleus. Understanding these concepts allows for the resolution of the problem.
elephantorz
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1. Through what potential difference (\DeltaV) would you need to accelerate an alpha particle, starting from rest, so that it will just reach the surface of a 15 x 10^(-15) m ^{238}U nucleus?
2. KE = q\DeltaV
E = \gamma_{p}mc²
r = \frac{mv}{qB}
3. Ok, I feel like I am close to what I really need but I am lacking something...
You can get the charge (q) and mass for both the particle and the U nucleus from the information given, you can also get the radius of the nucleus if needed.

I have that, I just seem to have two unknowns for every equation I am using, if I solve for u in E = \gamma_{p}mc² I don't know Energy, and if I solve for v or B in
r = \frac{mv}{qB} I don't know one of them, what am I missing?
 
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Where did the B come from?

If the alpha particle just reaches the surface of the nucleus, its KE is zero, but PE is not.

But how much KE it should have had to reach that point? Remember conservation of energy.

Knowing the charge of the alpha particle, what should be ∆V to give that KE at a point far away from the nucleus?

There, I just solved it for you.
 
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