What is the wavelength of an X-ray photon with energy 9.0 keV (9000 eV)? (1 eV = 1.60 × 10−19 joule.)

Express your answer to two significant figures and include the appropriate units.

2 answers

E = hν so
E = 9.0*10^3 ev * 1.60*10^-19 J/ev = 1.44*10^-15 J
ν = E/h
λ = c/ν = ch/E
0.14nm