Radiation with the minimum wavelength as well as the K x-ray lines are detected for a certain target.The energy of the incident electrons is then doubled, with the result that:
A)the minimum wavelength increases and the wavelengths of the K lines remain the same
B)the minimum wavelength decreases and the wavelengths of the K lines remain the same
C)the minimum wavelength and the wavelengths of the K lines all increase
D)the minimum wavelength and the wavelengths of the K lines all decrease
E)the minimum wavelength increases and the wavelengths of the K lines all decrease

Question

Quizplus · Accepted Answer

The minimum wavelength of the radiation emitted from the target is given by λ = hc/E, where h is Planck's constant, c is the speed of light, and E is the energy of the incident electrons. Doubling the energy of the incident electrons will result in a decrease in the minimum wavelength of the emitted radiation. The wavelengths of the K x-ray lines, on the other hand, are determined by the energy difference between the K and L electron shells of the target atoms. Doubling the energy of the incident electrons will not affect this energy difference and therefore will not change the wavelengths of the K x-ray lines. Therefore, the correct answer is B: the minimum wavelength decreases and the wavelengths of the K lines remain the same.

Radiation with the Minimum Wavelength as Well as the K