how are cathode rays produced ? briefly explain their important properties.
how are cathode rays produced ? briefly explain their important properties.
Cathode rays are nothing but beam of electrons observed in vacuum tubes. When a discharge tube or evacuated glass tube is facilitated with two electrodes positive (anode) and negative (cathode) and with an applied voltage, due to the emission of electrons from and travelling in the perpendicular to the cathode, the glass opposite of negative electrode is observed to glow.
Cathode rays are emitted by cathode in a vacuum tube and this is done by using Crookes tube or now modern vacuum tubes (or discharge tubes).
High electric potential is applied between anode and cathode to ionize the residual gas in tube.
The ions are accelerated by electric field and they collided with cathode which released electrons.
As electrons are negatively charged they are repelled by cathode and are attracted towards anode.
Electrons travel in straight line in the empty tube. They have high velocities and are colourless (invisible).
Their existence was detected as they struck the glass wall, excited the atoms of glass and made them to emit light, which is called fluorescence.
Any object placed in front of cathode cast the shadow on the glowing glass wall.
These electrons carried electric current through the tube.
Important properties of Cathode rays are:
1. Cathode rays travel in straight lines. That is why, cathode rays cast shadow of any solid object placed in their path.
2. Cathode rays consist of negatively charged particles. When cathode rays are subjected to an electrical field or magnetic field, these get deflected towards the positively charge plate (anode). These negatively charged particles are called electrons.
3. Cathode rays heat the object only which they fall. The cathode ray particles possess kinetic energy. When these particles strike an object, a part of the kinetic energy is transferred to the object. This causes a rise in the temperature of the object.
4. Cathode rays can penetrate through thin metallic sheets.
5. Cathode rays ionize the gases through which they travel.
6. Cathode rays travel with speed nearly equal to that of light.
7. Cathode ray particles had wave like behaviour.
Cathode rays are nothing but beam of electrons observed in vacuum tubes. When a discharge tube or evacuated glass tube is facilitated with two electrodes positive (anode) and negative (cathode) and with an applied voltage, due to the emission of electrons from and travelling in the perpendicular to the cathode, the glass opposite of negative electrode is observed to glow.
Cathode rays are emitted by cathode in a vacuum tube and this is done by using Crookes tube or now modern vacuum tubes (or discharge tubes).
High electric potential is applied between anode and cathode to ionize the residual gas in tube.
The ions are accelerated by electric field and they collided with cathode which released electrons.
As electrons are negatively charged they are repelled by cathode and are attracted towards anode.
Electrons travel in straight line in the empty tube. They have high velocities and are colourless (invisible).
Their existence was detected as they struck the glass wall, excited the atoms of glass and made them to emit light, which is called fluorescence.
Any object placed in front of cathode cast the shadow on the glowing glass wall.
These electrons carried electric current through the tube.
Important properties of Cathode rays are:
1. Cathode rays travel in straight lines. That is why, cathode rays cast shadow of any solid object placed in their path.
2. Cathode rays consist of negatively charged particles. When cathode rays are subjected to an electrical field or magnetic field, these get deflected towards the positively charge plate (anode). These negatively charged particles are called electrons.
3. Cathode rays heat the object only which they fall. The cathode ray particles possess kinetic energy. When these particles strike an object, a part of the kinetic energy is transferred to the object. This causes a rise in the temperature of the object.
4. Cathode rays can penetrate through thin metallic sheets.
5. Cathode rays ionize the gases through which they travel.
6. Cathode rays travel with speed nearly equal to that of light.
7. Cathode ray particles had wave like behaviour.
