To produce characteristic `X` - rays using a Tungsten target in an X - ray generator , the accelerating should be greater than ……. Volts and the energy of the characterization is …… eV .
(The binding energy of the intermost electron in Tungsten is - 40keV).

Answer

b

Explanation

For minimum accelerating voltage , the electron should jump from `n = 2 to n = 1` level `
For characteristic X-rays , `(1)/(lambda) = R_(alpha) (z - 1) ^(2) [1 - (1)/(n^(2))]`
`= R_(alpha) (z - 1) ^(2)`
But `E = h ( c)/(lambda) implies (1)/(lambda) = (E)/(hc)`
`:. (E)/(hc) = R_(alpha) (E)/(hc)`
implies (E_(1))/(E_(2)) = [[1 - (1)/(2^(2))]]/[[1 - (1)/(alpha^(2))]]`
` = E_(1) = (3)/(4) E_(2) = (3)/(4) 40.000 eV = 30.000 eV`