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 acceleration voltage (V), while the minimum wavelength `lambda_(c)` is inversely proportional to V. therefore, as V is increased, `lambda_(k)` remains unchanged where as `lambda_(c)` decreases or `lambda_(R)-lambda_(c)` will increase.