Early Quantum Theory: Problems
These are the math concepts which form the nucleus of these problems:
1) Einsteins photon energy equation: ________________________________
2) Einsteins photoelectric energy equation: ___________________________
3) Arthur Comptons photon momentum equation: ______________________
4) Louis de Broglies matter wave equation: ____________________________
5) Einsteins mass-energy equation: ___________________________________
6) Universal wave equation: ________________________________________
State the two conservation laws which pertain to any head on elastic collision: a) _______________________________________________________________ b) _______________________________________________________________
Physical Constants m e
= 9.1 x 10 -31 kg m p
= 1.67 x10 -27 kg h = 6.63 x10 -34 J.s c = 3.00 x10 8 m/s 1eV = 1.6 x10 -19 J
Problems
1.
Calculate the energy of a 400 nm photon (4.97 x 10 -19 J)
2.
What is the wavelength of a 4.6 eV photon (270 nm)
3.
In order to eject electrons from a metal whose work function is 3.9 x10 -19 J, what minimum frequency of light is needed? (5.9 x 10 14 Hz)
4.
Determine the wavelength of 0.01 kg stone traveling at 0.20 m/s (3.3 x10 -32 m)
5.
What kinetic energy must a proton have if it has a wavelength of 0.0011 nm? (1.1 x10 -16 J)
6.
How much total kinetic energy will an electron-positron pair have if produced by a 3.6 MeV photon? (2.58MeV)
7.
Calculate the momentum of a 400 nm photon. (1.67x10
-27 kg)
8.
In the Compton Effect, a 0.100 nm photon strikes a free electron in a head on elastic collision and knocks it in the forward direction. The rebounding photon recoils directly backwards. Use the collision conservation laws to find: a.
The kinetic energy of the electron. (9.2 x 10 -17 J) b.
The wavelength of the recoiling photon (0.104m)

Answers

Answers