The intensity of X-rays form a Coolidge tube is plotted against wavelength `lambda` as shown in the figure. The minimum wavelength found is `lambda_c` and the wavelength of the `K_(alpha)` line is `lambda_k`. As the accelerating voltage is increased
(a) `lambda_k - lambda_c` increases (b) `lambda_k - lambda_c` decreases
(c ) `lambda_k` increases (d) `lambda_k` decreases

Options

A. `(lambda_(K) - lambda_(C ))` increases
B. `(lambda_(K) - lambda_(C ))` decreases
C. `lambda_(K)` increases
D. `lambda_(K)` decreases

Answer

A

Explanation

Wavelength `lambda_(K)` is independent of the accelerating voltage `(V)`, while the minimum wavelength `lambda_( C)` is inversely proportional to `V`. Therefore as `V` , `lambda_(k)` remains unchanged whereas `lambda_( c )` decreases or `lambda_(k) - lambda_(c )` will increase.