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H_Psi

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I am starting to learn the basics of QED and I am trying to get acquainted with the units and scales that are used.

## Homework Equations

The exercise is to estimate the energy, time and length that correspond to the mass of an electron.

## The Attempt at a Solution

That’s what I did:

The mass of an electron is 9.11E-31 kg.

Energy:

E=mc^2 gives me an energy of 0.511MeV.

Length:

Here I used the equation: c * hbar = 197 MeV * fm

-> 386fm = c * hbar / (0.511MeV)

-> In natural units: 386fm = 1 / (0.511MeV)

Time:

Here I used the equation: hbar = 6.58E-22 MeV * s

-> 1.288E-21 s = hbar / (0.511MeV)

-> In natural units: 1.288E-21 s = 1 / (0.511MeV)

Is this calculation correct? Is that the way one can calculate the length and time corresponding to a mass?

Thanks