principles of classification

If a body is in equilibrium under the action of a number of forces, then the algebraic sum of the moments of the forces about any point is equal to zero. In other words, the sum of the clockwise moments equals sum of the anticlockwise moments when the body is in equilibrium. ..

It is not possible to measure simultaneously both the position and velocity (or momentum) of a microscopic particle with absolute accuracy or certaint..

The dual of any statement in a Boolean algebra is the statement obtained by interchanging + and ., and simultaneously inter-changing the elements 0 and 1 in the statemen..

If two events E 1 and E 2 can occur independently in exactly m ways and n ways respectively, then either of the two events can occur in (m + n) way..

A floating body displaces an amount of fluid equal to its own weigh..

An iron needle sinks in water but a huge ship floats on the surface of water. All objects whether inside the liquid (or fluid) or partially inside, appear to be lighter than in air. This is because liquids (or fluids) exert upward force on the immersed object. This is called the upthrust, the Buoya..

Christian Huygen Huygen proposed a hypothesis for the geometrical construction of the position of a common wavefront at any instant during the propagations of waves in a medium. The postulates are: Every point on the given wavefront called 'primary wavefront' acts as a fresh source of new dis..

The Le Chatelier's principle has a great practical significance for all physical and chemical systems. Applicability of this principle to some of the systems is described bel..

Pauli's Exclusion Principle - According to this principle, an orbital can accommodate maximum of two electrons and these two must have opposite spins. This means that an orbital can have 0, 1 or 2 electrons. Moreover, if an orbital has two electrons, they must be of opposite spi..

Principle of Homogeneity of Dimensions - It states that if the dimensions of each term on both the sides of equation are same, then the physical quantity will be corre..