- #1
skg94
- 79
- 0
Homework Statement
1. A photon with an initial energy of 33eV collides with an electron. If the speed of the electron after the collision is 4.56*10^5m/s the final energy of the photon is? [32.4eV]
2. Photons that compose a monochromatic beam of light each have a momentum of 1.50*10^-28 kgm/s. The period of this light [1.47*10^-14s]
3. an xray photon of wavelength .010nm strikes a helium nucleus (alpha particle) and bounces straight back. If the helium nucleus was originally at rest, calculate its velocity after interacting with the x-ray [2*104m/s]
4. A photon moving in an easterly direction with an energy of 6.21 *10^-15 J collides with an electron and scatters at an angle of 30 W of S. What is the velocity of the electron after the collision? [3.74 *10^7m/s [28 N of E]]
5. Calculate the frequency of an electron that has a speed of 9.2*10^5m/s [1.16*10^15hz]
Homework Equations
e=hf
E=1/2mv^2
conservation of momentum/energy
p=mv or h/lambda
The Attempt at a Solution
1.Energy of photon before = energy of electron after + energy of photon after.
energy of photon after = energy of photon before - energy of electron after
Ea = 33eV - (1/2 (9.11*10^-31) (4.56*10^5)^2)
i get 33eV seeing as how the energy of the electron is 9.47*10^-20 very small i can see why, what did i do wrong? this is my attempt maybe i did the whole thing wrong?2. I have no idea how to relate momentum of a photon (p=h/lambda) to time, no velocity some help here?
3. Is this conservation of energy? I tried hf=1/2mv^2 , but it didnt make sense and didnt work when you solve for v.
4. Am i not missing something in this question for conservation of energy i believe i don't have enough information, or at least i can't get it.
5. lambda = h/mv
lambda =(6.63*10^-34)/(9.11*10^-31)(9.2*10^5) =7.910 *10^-10 m
f = c/lambda = 3.79*10^17
i don't where else to get frequncy.. can't use Ek=hf
Last edited: