When 40 kV is applied across an X-ray tube, X-ray is obtained with a maximum frequency of `9.7 xx 10 ^18` Hz. Calculate the value of Planck constant from these data.

Explanation

Given `v=40KV,f=9.7xx10^18Hz `
we know , `lambda=(hc)/(eV) `
or `lambda/c=h/(eV) `
` or 1/f=h/(eV) `
` or h=(eV)/f V-s `
` =V/f 2V-s `
` (40xx10^-3)/(9.7xx10^18)xxe `
` 4.12xx10^-15eV-s`