What is the energy of the X rays?

Question

Hospital X-ray generators emit X rays with wavelength of about 15.0 nanometers ( nm), where 1 nm = 10^-9 m.

Answer 1

E = hc/lambda
E is energy
h is Planck's constant = 6.626 x 10^-34
c is speed of light = 3.00 x 10^8 m/s
lambda is wavelength = 15.0 x 10^-9

E = (6.626 x 10^-34)(3.00 x 10^8) / (15.0 x 10^-9)