Question

If the operating voltage of the x-ray tube is 50kV then the velocity of X-ray is:
(A) \[7.5 \times {10^{25}}\dfrac{m}{s}\]
(B) \[3 \times {10^8}\dfrac{m}{s}\]
(C) \[{10^8}\dfrac{m}{s}\]
(D) 3 \[\dfrac{m}{s}\]

Answer 1

Hint The speed of light or EM waves is independent of the medium around them. It is also independent of the frequency and wavelength of that particle-wave

Complete step by step solution In an x-ray tube, the filament is heated using current. It then emits electrons. These electrons are further attracted to the positively charged anode. The electrons collide and interact with the atoms present on the perforated anode. This interaction is the cause of the production of x-ray beams in the x-ray tube.
X ray waves are a form of EM waves and all EM waves travel with the speed of light in a vacuum. Therefore whatever may be the operating voltage of the x-ray tube, the waves will travel with the speed of light.

Therefore the correct answer is option B.

Note: The X ray waves have a range of wavelengths from ${10^{ - 8}}$ to ${10^{ - 12}}$ and at all wavelengths they would travel at the same speed. Increases the wavelength will only decrease the frequency which will further impact the total energy of the wave