How are cathod rays produced?

Cathode rays are produced when a high voltage is applied between a cathode and an anode in a vacuum tube. The cathode is a negatively charged electrode, while the anode is a positively charged electrode. When the voltage is applied, electrons are emitted from the cathode and travel towards the anode. These electrons are called cathode rays.

The production of cathode rays can be explained by the photoelectric effect. When light strikes a metal surface, it can cause electrons to be emitted from the surface. This is because the energy of the light quanta (photons) is transferred to the electrons, giving them enough energy to overcome the attractive force of the metal atoms and escape from the surface.

In a cathode ray tube, the cathode is heated to a high temperature. This causes electrons to be emitted from the surface of the cathode by thermionic emission. Thermionic emission is the emission of electrons from a hot surface. The electrons emitted from the cathode are then accelerated towards the anode by the high voltage applied between the electrodes.

The cathode rays can be focused into a beam by using a magnetic field. The magnetic field causes the electrons in the cathode rays to move in a circular path. The radius of the circle is determined by the strength of the magnetic field and the speed of the electrons. By adjusting the strength of the magnetic field, the cathode rays can be focused to a point.

Cathode rays are used in a variety of applications, including television sets, electron microscopes, and X-ray machines. In television sets, cathode rays are used to create the image on the screen. In electron microscopes, cathode rays are used to magnify objects. In X-ray machines, cathode rays are used to produce X-rays.