Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. It's 100% free.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top


An unstable particle produced in a high-energy collision is measured to have an energy of $483\ \mathrm{MeV}$ and an uncertainty in energy of $84\ \mathrm{keV}$. Use the Heisenberg uncertainty principle to estimate the lifetime of this particle.

Attempt at answer: I thought $$ (\Delta E)(\Delta t) = \hbar = 1.055 \times 10^{-34}\ \mathrm{J}\cdot\mathrm{s} = 6.591 \times 10^{-16} \mathrm{eV}. $$

So I tried solving for $\Delta t$, my time, with $\Delta E = 84\ \mathrm{keV}$. However, this answer is wrong (I get something like $7.85 \times 10^{-21}\ \mathrm{s}$, which is incorrect). I assume I'm supposed to incorporate $483\ \mathrm{MeV}$ somehow, but am not sure how. Any suggestions?

share|cite|improve this question

closed as off-topic by David Z Nov 1 '13 at 3:28

This question appears to be off-topic. The users who voted to close gave this specific reason:

  • "Homework-like questions should ask about a specific physics concept and show some effort to work through the problem. We want our questions to be useful to the broader community, and to future users. See our meta site for more guidance on how to edit your question to make it better" – David Z
If this question can be reworded to fit the rules in the help center, please edit the question.

Hi user23254, and welcome to Physics Stackexchange. I added the homework tag appropriate for problems where guidance is better than straight-up answers. Also note that we support LaTeX-style markup to make things easier to read - you can see how I formatted the equations by editing the post. – Chris White Apr 17 '13 at 3:50
Your calculation looks OK to me. What answer were you expecting to get? – John Rennie Apr 17 '13 at 9:25