e = charge of electron = 1.6e-19
heV = Planck constant (eV⋅s) = 4.135e-15
hJ = Planck constant (J⋅s) = 6.626e-34
a. E = heVc/λ = 1240/λ
b. N = %*(A/4πD2)*(P/E) = %*(A/4πD2)*(Pλ/hJc)
c. N' = Nλ2/λ1
3.2: Photoelectric Effect
a. V = heVc/λ-Φ = 1240/λ-Φ
b. N = photons/sec = P/E = P/(hJc/λ) = Pλ/(hJc)
c. Imax = N*e
d. hf-Φ=h(f-fc) ∴ fc=Φ/heV
3.3: Duane-Hunt Law
b. E = Ee*e
c. λ = heVc/Ee = 1240/Ee
3.4: de Broglie Waves
b. The interference pattern is the same as for the neutrons, and the grating has the same spacing
So it is the same as λ from part (a)
c. E=heVc/λ-Φ (keep λ in nm and heVc=1240, then convert eV to keV)
d. p=/λ since λxray=λneutron pxray/pneutron=1
NOTE ABOUT HOMEWORK B: THESE ANSWERS MAY NOT BE CORRECT. USE THEM AT YOUR OWN RISK.
HomeworkB 03 ------------
Questions 1, 2, and 3 refer to the picture inside a TV set which accelerates electrons to 26 keV.
1) What is the wavelength λe of the electrons inside the set?
2) If photons have the same wavelength as the electrons in this TV tube, compare their momentum pγ with the momentum of the electrons pe
pγ = h/λ = pe
3) What is the wavelength λγ of photons which have the same energy as the electrons, Eγ=26keV?
Questions 4 and 5 look like these two waves (λ1=1.5L ; λ2=L)
4) Assume that the two waves represent photons of wavelengths λ1 and λ2. Compare the energy of these two photons.
5) Assume that the two waves represent electrons of wavelengths λ1 and λ2. Compare the energy of these two electrons.
divide these two equations yields E1=.44E2