SCI 270: On Nuclear Technology Practice Problems

## 2. Natural Units: electrons, atoms, molecules, and natural constants

1. Express the rest mass of an electron in the following units. Please use 1e-6 to mean 10-6 in your expressions.

 ___________ J ___________ MeV ___________ g ___________ kg ___________ amu

2. Complete this table for the properties of an electron.

Charge in C Charge in esu Spin Magnetic moment

________________

________________

________________

________________

3. Give these fundamental constants so that you are familar with the physical quantities.

 Charge for one mole of electron F = _____________ C Avogadro's number NA = _____________ particle mol-1 Estimate the charge of an electron from the two quantities given above __________________________ The Planck constant h = _____________ J s-1

4. An electron has a kinetic energy of 1 eV. Give the following:

 Kinetic energy = __________________ J Velocity of the electron __________________ m/s

 Force = _____________ N

5. Estimate the Coulomb force of attraction when the electron is 53 pm (1 pm = 1e-12 m) from a proton. This is the Bohr model for the H atom.

6. To decompose 36 g of water, 4 F charges must pass through the electrodes. If the voltage applied is 1.23 V, calculate the energy required for this decomposition.

 36 g water = _____________ mol Number of molecules in 36 g water = _____________ molecules Number of atoms in 36 g water = _____________ atoms Energy = _____________ keV Energy required to decompose a water molecule = _____________ keV