## CRYSTAL STRUCTURE | Packing fraction| sc , bcc, fcc| CRYSTAL DIFFRACTION| Bragg’s law |Von Laue equation of scattering vector

Packing fraction The ratio of the volume of the atoms occupying the unit cell to the volume of the unit cell relating to that structure is called packing fraction. i.e.   Packing factor (f) = volume of the atoms per unit cell (v) / Volume of the unit cell (V) Atomic radius : The atomic radius … Read more

## CRYSTAL STRUCTURE | Classification of solids| Lattice and lattice points, Crystal structure| Bravais space lattice| Unit cell, Primitive cell| Miller indices.

Classification of solids The solids are categorised into categories – A. Crystalline solids.         B. Amorphous solids. Distinction between crystalline and amorphous solids – i) Crystalline solids have a regular arrangement of particles whereas the amorphous solids have a completely random particles arrangement. ii) Crystalline solids have different physical properties ( eg. – Thermal conductivity, electrical conductivity … Read more

## CLASSICAL MECHANICS | Discuss the effect of Coriolis force in case of a freely falling body on the

Discuss the effect of Coriolis force in case of a freely falling body on the surface of the earth and calculate the deviation from the vertical suffered by a body dropped from rest from a height h.( or Deflection of a body, falling freely, due to Coriolis force) : Let P be a point at … Read more

## CLASSICAL MECHANICS| Acceleration of a particle| Coriolis force and Centripetal force

Acceleration of a particle with respect to a not rotating frame of reference Let us consider an inertial frame of reference S (x, y, z) and an non inertial frame of reference S'(x’,y’,z’) where origin of both frames coincide and S’ is rotating with constant angular velocity with respect to S frame.   Let P(x, … Read more

## CLASSICAL MECHANICS | Virtual displacement| D’Alembert’s principle| Frame of Reference

Virtual displacement The virtual displacement is called ‘virtual” in the sense that there is no passage of time during such a displacement (But actual displacement dr does occur in a finite though small interval of time dt). Virtual displacement is consistent with the forces and constraints imposed on the system at a given instant t. … Read more

## CLASSICAL MECHANICS | Constraints| Generalised co-ordinates| Degrees of freedom

Constraints In practice, the motion of a particle or system of particles generally restricted in some ways e.g.   i) The motion of rigid body is always such that the distance between two particles remain unchanged.            ii) The motion of simple pendulum/point mass is such that the point mass and … Read more