PHYSICS · Single correct · A Level · Physics · Medical physics · Medical physics
Problem
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 2I , the potential difference V is increased to 2V , and the separation distance d is reduced to 2d , 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