Question

Assertion: Anode of Coolidge tube gets heated up at time of emission of X− rays.
Reason: The anode of the Coolidge tube is made of a material of high melting point.
A. If both assertion and reason are true and the reason is the correct explanation of the assertion.
B. If both assertion and reason are true but reason is not the correct explanation of the assertion.
C. If the assertion is true but the reason is false.
D. If the assertion and reason both are false

Answer 1

Hint: We should keep in mind some fundamental ideas about the Coolidge tube and X-rays in order to answer this topic. The source of electrons in a Coolidge tube is a heated filament and it has a high vacuum. In contrast to cold cathode gas discharge tubes, the tube contains so little gas that it is not necessary for the creation of x-rays.

Complete step by step solution:
The Coolidge ray tube can be used to create X-rays in a laboratory. The Coolidge tube's stability and capacity to independently alter X-ray energy and intensity are its two main advantages. The temperature of the cathode rises as the current to it is increased. This boosts the cathode output of electrons, which in turn enhances the X-rays' intensity.

The velocity of the electrons impacting the anode increases with an increase in the high voltage potential difference between the anode and the cathode, which in turn increases the energy of the emitted X-rays. In the Coolidge tube, an electric current heated tungsten filament produces electrons via the thermionic effect. The cathode of the tube is the filament.

The anode is where the electrons strike after being accelerated by the high voltage potential between the cathode and the anode. Therefore, filament current regulates the intensity of X-rays. And during this procedure, the incoming electrons give the X-rays that are emitted from the sample a boost in energy. The amount of energy transferred determines the X-rays' maximum energy (or minimum wavelength).

When a fast-moving electron collides with a target's atoms, the majority of its kinetic energy is used to intensify the target's atoms' thermal agitation; very little of it is released as X-ray radiation. As a result, the target's temperature increases.

Hence option B is correct.

Note: The cathode filament emits electrons as it warms up. The amount of electron emission increases as the filament heats up. These electrons are driven in the direction of the positively charged anode, where they change course and release x-rays with a wide variety of energies. The kinetic energy of the electrons impacting the anode is equal to the maximal energy of the x-rays.