what is cathode rays ?
Answers
Cathode Rays :
A discharge tube is a long glass tube at the two ends of which are sealed two metal plates . These ways can be connected to a high voltage source and are called electrodes . The electrode connected to the negative terminal of the source is called the cathode , and the one connected to the positive terminal is called the anode . There is also a side tube which can be connected to one exhaust pump, used for lowering the pressure of the gas inside the discharge tube.
When I voltage is applied across the terminals, and the pressure inside the tube is 0.01-0.001mm of mercury, the end of the tube opposite the cathode starts glowing . This phenomenon is called fluorescence . Investigations have shown that sum in visible rays, starting from the cathode , fall on the opposite word of the tube, causing fluorescence . These rays were named cathode rays .
The characteristics of cathode rays :
Sir J J Thomson and others found that cathode rays have the following characteristics.
1. They originate at the cathode and travel in straight lines.
" When an object is placed in the path of cathode rays, a shadow of the object falls on the wall opposite of the cathode . A Shadow can be formed only when the rays travel in straight lines ".
2. Cathode rays are a stream of particles.
" A light paddle wheel, placed in the path of the cathode rays, rotates . This shows that some particles strike the plates of the wheel ".
3. The particles constituting cathode rays are negatively charged.
" This is provided by the fact that the cathode rays bend towards the positive plate in an electric field ".
4. The particles constituting cathode rays are all alike . They do not change with the gas, the electrodes and the kind of glass used for making the tube .
" Thus , Sir J J Thomson concluded that the particles constituting cathode rays for a Universal constituent of all atoms . These particles where named electrons in 1897 .
Hope it helps you.....
✪ Cathode Rays ✪
Let us start from the basics...
What is cathode? Cathode is a negatively charged electrode and attracts positive charges.
Cathode rays are the such rays which are generally observed in certain high-level vaccum tubes as the streams. Cathode ray travels through cathode to the anode. Thus his it can be said, from the negatively (-) charged electrode to the positively (+) charged electrode.
They move from cathode to anode because, they are self negatively charged and thus they get attracted to the positive charges. In case, cathode rays are generally deflected in magnetic fields along with the electric fields.
Scientist named JJ Thomson discovered that the cathode rays always represent the negative charges and thus it is said according to it, cathode rays are made up of negative charges.
In cathode ray experiment, He also discovered that certain and different metals emit cathode rays which are usually made up of small negative particles, named electrons.
Cathode rays represent the focus of small negative particles called electrons in a beam, which are generally deflected in magnetic fields along with the electric fields.