# Calculate KE, E, p and f for proton.

1. Oct 13, 2012

### budafeet57

1. The problem statement, all variables and given/known data
photon(0 MeV), electron(0.511MeV), photon(938 MeV) have wavelength of 2.0*10^-15 m, 2.0pm. Calculate their kinetic energy, total energy, momentum, all in MeV, and velocity and frequency.

2. Relevant equations
E = K + mc^2
E^2 = (pc)^2 + (mc^2)^2
E=hf
λ=h/p

3. The attempt at a solution
for photon:
K 0.621 MeV
E 0.621 MeV
p 0.621 MeV/c
v 3*10^8 m/s
f 1.5*10^20 Hz

for electron:
K 0.292 MeV
E 0.803 MeV
p 0.62 MeV/c
v 0.77 c
f 1.94*10^22 Hz

for proton:
K 0.0002 MeV
E 938.0002 MeV
p 0.62 MeV/c
v 6.6*10^-4 c = 1.98*10^5 m/s
f 2.2*10^23 Hz

I am a little bit not sure about my results regarding proton's. Any help verifying my answers will be appreciated because I don't have answer for this problem.

2. Oct 13, 2012

### frogjg2003

You're right, but your rounding is a little weird. You have only two digits for p, but then you have 7 digits for E. With any reasonable rounding, you would have 2/3 digits for E and just get 0 for K.

3. Oct 13, 2012

thank you.