Chemistry Project Report on “Radio Activity”
I, ____________ student of ___________________ is doing
project report entitled “Radio Activity” being submitted to
___________________is an original piece of work done by me.
In ordinary chemical combinations, only the electron present in the outermost orbital's are involved i.e. they are transferred from one atom to the other atom remain unaffected. However, there are certain phenomenon in which the nucleus of atom is involved. "The branch of chemistry dealing with the phenomena involving the nucleus of the atoms is known as NUCLEAR CHEMISTRY".
In fact, the only phenomena involving the nucleus of an atom are RADIOACTIVITY both natural and artificial.
NATURAL RADIOACTIVITY :
The phenomenon of spontaneous emission of certain kinds of radiation by some elements is called radioactivity or natural radioactivity.
ARTIFICIAL OR INDUCED RADIOACTIVITY :
The phenomenon in which the artificial disintegration of a stable nucleus leads to the formation of a radioactive isotope is called artificial radioactivity.
NATURE AND CHARACTERSTICS OF RADIOACTIVE SUBSTANCES
It is observed that on applying the field, the rays emitted from the radioactive substances are separated into three types called ALPHA, BETA, GAMMA rays.
The ALPHA rays are deflected in a direction which shows that they carry positive charges the BETA rays are deflected in the opposite direction and the GAMMA rays are not deflected at all showing that they carry no charge.
PROPERTIES OF ALPHA RAYS
The direction of deflection of the ALPHA rays in the electric and magnetic field showing that they carry positive charge. It is found that each ALPHA particles carries two units of positive charges and has mass nearly four times that of hydrogen atom.
The velocity of ALPHA rays is found to be nearly1/10th to 1/20th of that of light, dependent on the nature of source.
ALPHA rays ionize the gas through which they pass.
ALPHA rays have low penetrating power. They can penetrate through air only to a distance of about 7 cm.
ALPHA rays affect photographic plate and produce luminescence when they strike zinc sulphide screen.
PROPERTIES OF BETA PARTICLES
The direction of deflection of BETA rays in the electric and magnetic field shows that they carry negative charge. These particles possess the same charge and mass as that of electron.
The velocity of BETA rays depends upon the nature of the source. The speed of particles varies from 3% to 99% of that of light.
The ionizing power of BETA particles is about 1/100th of that of ALPHA particles.
There penetrating power is about 100 times greater than that of ALPHA rays.
Like ALPHA rays, BETA rays affect a photographic plate and the effect is much higher. However, there is no significant effect on a zinc sulfide screen become of their lower kinetic energy.
PROPERTIES OF GAMMA RAYS
They are not deflected in the electric and magnetic fields showing these by that they do not carry any charge.
They travel with the some velocity as that of light.
As they do not have any mass, their ionizing power is very poor.
Their penetrating power is about 100 times more than that of BETA rays. Thus they can penetrate through lead sheets as thick as 150mm.
GAMMA rays have very little effect on the photographic plate or zinc sulphide screen.
Physics Project Reports CBSE Free Download School Students Notes