# Tag Info

## Hot answers tagged heisenberg-uncertainty-principle

### If you knew perfectly knew the initial state of everything, could you predict everything?

Due to the Heisenberg Uncertainty Principle, one cannot know the complete state of a system, or particle. That's not quite right. You can know the complete state. That is, it's possible to prepare a ...
1 vote
Accepted

### Explain Heisenberg's uncertainty principle

The expected answer is direct. A particle in a stationary state in the box has zero averaged momentum, just because the particle stays there stationarily. Hence $(\Delta P)^2 = \langle P^2\rangle$ ...
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1 vote

### Why can protons and neutrons be close together in a nucleus despite the uncertainty principle?

The general rule for the size of a bound state is: $$R = \frac{\lambda_C}{2\pi\alpha}$$ where $$\lambda_C = \frac{hc}{mc^2} = \frac{h}{mc}$$ is the Compton wavelength of the bound particle, and \$\...
• 24.6k
1 vote
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### Why can protons and neutrons be close together in a nucleus despite the uncertainty principle?

Momentum is mass times velocity. Electrons have a teeny tiny mass (that's the technical term). Protons and neutrons are, relatively speaking, much much bigger (note, I'm not weight shaming any protons ...
• 24.1k
1 vote

### If you knew perfectly knew the initial state of everything, could you predict everything?

If you knew perfectly knew the initial state of everything, could you predict everything? If you study physics, you will learn that it is a discipline which observes and measures quantities in nature ...
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