I'm revising for a QM exam but some of this question is A-level-ish
I'm simpley not getting the answers provided, which are after each question in brackets
A1: Caluclate the wavelegnth of the following:
a) a 10eV photon ()
b) an electron with a kinetic energy of 10eV ()
c) a thermal neutron of average kinetic energy in a neutron gas of temperature 300K ()
d) a tennis ball with mass of 57g travelling at 50m/s ()
Does anyone actually get these answers?
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energy and de broglie question watch
- Thread Starter
- 13-04-2011 16:10
- 13-04-2011 16:32
I make (a) 1.2 x 10^-7 m; I can't see where their answer comes from.
I agree with (b). First work out the velocity of the electron, then use the de Broigle equation (ignoring relativistic effects).
I don't have the knowledge to comment on (c).
I agree with (d); it's a straightforward application of the de Broigle equation.
- 13-04-2011 17:31
for c) you can find the average translational kinetic energy of the neutron, given by (3/2)kT where k is the boltzmann and T is temperature in kelvin. plug that into KE=(p^2)/(2m) to find momentum of the neutron and voilaLast edited by Bjoorn; 13-04-2011 at 20:13.
Last edited by jaroc; 13-04-2011 at 17:48.
- 13-04-2011 17:35
- 13-04-2011 17:38