Photon energy question

Question

What is the accelerating voltage of an x-ray tube that produces x rays with a shortest wavelength of 0.0103 nm?

Answer 1

1 nanometer = 1.0 × 10^ -9 meters

0,0103 nanometer = 1,03*10^ -11 meters

e Va = hc\λmin

where e is the electronic charge = 1,6*10^ -19 Columbs

Va the accelerating voltage applied to the x-ray tube

h is planck's constant 6,625*10^ -34 Js

c is the speed of light

λmin is the shortest wavelength

So

Va = (hc\λmin) \ e

= ((6,625*10^ -34)*(3*10^8)\(1,03*10^ -11)) \ 1,6*10^ -19 = 120600,7 V

Answer 2

Energy = hf

f = c/L

frequency = 2.9 x 10^15 Hz

Energy = 1.205 x 10^5 eV

Voltage = 1.2 x 10^5 volts