When a beam of accelerated electrons hits a target , a continuous `X` - ray spectrum is emitted from the target. Which of the following wavelength is absent in `X` - ray spectrum , if the `X` - ray tube is operating at `40,000 "volts"`?

Options

A. `0.25 Å`
B. `0.5 Å`
C. `1.5 Å`
D. `1.0 Å`

Answer

A

Explanation

`lambda_(min) = (12375)/(40,000) = 0.3 Å` , Hence wavelength less than `0.30 Å` is not possible .