Biripali

                            Solids:-    Sol ids : The solids are the forms of matter in which atoms ands molecules are strongly bound and maintain definite volume and sharp unless changes by applying external forces. Solid state physics: - The solid state physics is the study of the physical properties of the atomic/molecular matter in the solids state. These physical properties include crystal structure, bonding,thermal, electric and magnetic properties. Classification of solids:         Solids are classified into two categories; (1) crystalline solids (2) Amorphous solids. (1) crystalline solid :-        The crystalline solids are defined as an ordered periodic arrangements of atoms, molecules or ions . Properties of crystalline solids:- • The internal arrangements of atoms,ions or molecules of crystalline solids is in a definite order. • The crystalline solids have ...

Post ulates of kinetics theory :-        Suppose a container with volume v contain a very large numbers N of identical molecules,each with mass m. Then, the kinetics theory postulates the following- (1) The molecules behave a point particles that are small compared to the size of the container and to the average distance between molecules. (2) The molecules are in constant motion. Each molecules collides occasionally with a wall of the container. These collisions are perfectly elastic. (3) There is no force of attraction among the gas molecules and between the gas molecules and walls of the container. (4) The container walls are right and infinitely massive and do not move. (5) The molecules obey Newton's law of motion. (6) The time of collision is much less than the averaged time between two successive collision. Meaning of elastic collisions:- If a molecule with velocity u strikes a wall align along y-axis, then the collision is elastic if • velocity componen...

Coulomb's Law : The electrostatic force of interaction between two static point electric charge is directly proportional to the product of the charge, inversely proportional to the square of the distance between them and acts along the straight line joining the two charges. If two points charge q1 and q2 separately by a distance r. Let F be the electrostatic force between these two charge. According to Coulombs law.

I) In term of energy:-       Kinetic energy of a potential of mass m moving with velocity v is given by Where p is momentum of particles Therefore, We knowing that de- Broglie wavelength                  λ= h/p Therefore,   ........................(1) II) In term of temperature:-  From kinetic energy of gases, the average kinetic energy of a material particles at temperature T is given by Where k is Boltzmann constant. The value of k= 1.38 x 10^-23 J/k Putting this value in eq (1), we get Therefore, ...................(2)

Electric charge: Charge is the property associated with matter due to which it produces and experience electrical and magnetic effect.The excess or deficiency electrons in a body gives the concept of charge. Types of charge: 1. positive charge: It is deficiency of electrons as compared to protons. 2. Negative charge: It is excess of electrons as compared to proton. S.I. Unit of charge is Coulomb Dimensions: [A T] 1C = 3 x 10^9 stat coulomb,  1 absolute coulomb= 10C, 1 faraday = 96500C Specific property of charge: - Charge is a scalar quantity . - Charge is transferable. - charge is always associated with mass. - Charge is quantised. Q=ne - Charge is conserved. - Charge is invariant.

MATTER WAVE :-          In 1924 de-broglie proposed that matter also has a dual nature just like radiation. His hypothesis about the dual nature of matter was base on following observations.   I) The whole universe is composed of matter and electromagnetic radiation.   II) The nature loves symmetry . As the radiation has dual nature, matter should also possess dual nature.          According to de-broglie, a wave is associated with every moving material particles. These waves are called de-broglie waves or matter waves.     According to quantum theory, energy of a photon is given bye                   E= hv   Where h is Planck's constant and v is frequency of radiation. Relativistic energy of a particle is given by Sine rest mass of photon is zero i.e mo= 0 Then  E= pc            hv= pc  Momentum o...

Radioactivity: The uranium salt emitted the rays spontaneously.The phenomenon of spontaneous emission of radiations by heavy elements is called Radioactivity . Properties of nuclear radiation: 1. Properties of Alpha(α) rays: - Alpha(α) particles is a helium nucleus consisting of two protons and two neutrons. - The velocity of α- particles ranges from 1.4 x 10^7 m/s to 2.05 x 10^7 m/s. -They are deflected by electric and magnetic fields. - Alpha (α) particles produce fluorescence in substance like zinc sulphide and barium platinocyanide. - They are massive particles and hence easily stopped by an aluminium sheet of only 0.02mm thick or even by ordinary sheet of paper. - They have great ionising power. Each α-particles produces thousands of ions pairs in a gas before being absorbed. - They get scattered while passing through this metal foils. - They affect a photographic plate. - They can produce artificial radioactivity in certain elements and can produce nuclea...