Photon fluence and energy fluence question, all work shown

[johnq2k7]

An x-ray field at a point P contains 7.5 x 10^8 photons /m^2-sec-keV uniformly distributed from 10 to 100 keV.

a.) What is the photon flux density at P?
b.) What would the photon fluence in one hour?
c.) What is the corresponding energy fluence in SI units?


my work:

a.) 7.5 x 10^8 photons/ (m^2-sec-keV) * (100- 10 keV) = 8.3 x 10^6 photons/(m^2-sec)

b.) 8.3 x 10^6 photons/(m^2-sec) * (3600 sec/hr)= 3.0 x 10^10 photons/m^2

c.) 7.5 x 10^8 photons/ (m^2-sec-keV) * (1 keV/1.602 x 10^-16 J)
= 1.7 x 10^28 photons/(m^2-J)

I have shown my work, but I'm confident with my answers please help!

 

[mark726]

Your answers for parts a and b are correct. For part c, you have correctly converted from keV to Joules, but the units for energy fluence should be J/m^2, not photons/m^2. So the correct answer for part c would be 1.7 x 10^28 J/m^2.