What is the minimum potential difference?

[sweetipie2216]

What is the minimum potential difference applied to an x-ray tube if x-rays of wavelength 0.250 nm are produced?



E=hf
f=c/wavelength

f=3e8/.250e-9
=1.2e18

then i applied it to the first equation using Plancks constant as h and my final answer came out to be 7.95e-16 KV.

the answer is wrong. can you please help me out? thanks.

 

[Chewy0087]

half way there,

the work done accelerating the electrons is equal to $$eV$$, but you can also find out the energy of the xrays, as you've shown, these energies should be equal.

you worked out the energy of the xrays, not the voltage.