Question

The hardness of X rays by Coolidge tube depends upon
A) Filament Current
B) Air Pressure in tube
C) Material of target
D) The potential between target and cathode

Answer 1

Hint: X-Ray is basically an electromagnetic wave of very high energy which is made to focus on some point. It has a comparatively short wavelength. It has the ability to pass from opaque to light. X-Rays depend on some factors like hardness, intensity, etc.

Complete step by step solution:
Step I:
The hardness of an X-Ray means the quality or amount of the radiation focused. Since X-Rays have a shorter wavelength, so they are comparatively more energetic than soft rays. The hardness of the X-rays depends on the voltage on which it is operated. Therefore, it can be increased or decreased by controlling the potential voltage.
Step II:
The-Ray has basically two elements: one is the cathode and the other one is anode. A cathode is a small coil of wire which is made in the form of a cup-shaped region. The cathode acts as a path to the electrons and expels the electrons from the circuit in the form of a well defined focused beam. While anode of the X-Ray tube acts as a target or the focus spot on which the electrons coming from the cathode are made to focus or fall. The anode further releases X-Rays.

$\therefore $ The hardness of X-Rays by Coolidge tube depends on the potential between target and cathode. Option (D) is the correct answer.

Note:
There is a difference between the intensity and hardness of the X-Rays. Hardness refers to the quality of the radiation focused, whereas intensity refers to the quantity of the radiation light focused per unit area on the target. Hardness can be adjusted by controlling the voltage of the incident beam and then by varying the intensity of the current.