In an X-ray tube, electrons emitted from a filament (cathode) carrying current I hit a…

Physics · JEE Advanced · NTA Exams — Atoms and Nuclei

In an X-ray tube, electrons emitted from a filament (cathode) carrying current I hit a target (anode) at a distance d from the cathode. The target is kept at a potential V higher than the cathode resulting in emission of continuous and characteristic X-rays. If the filament current I is decreased to the potential difference V is increased to 2V, and the separation distance d is reduced to then

1. the cut-off wavelength will reduce to half, and the wavelengths of the characteristic X-rays will remain the same
2. the cut-off wavelength as well as the wavelengths of the characteristic X-rays will remain the same
3. the cut-off wavelength will reduce to half, and the intensities of all the X-rays will decrease
4. the cut-off wavelength will become two times larger, and the intensity of all the X-rays will decrease.