Energy – Whenever we do any work, we feel tired as we expend some energy. Energy spent appears in the form of work done. Energy is defined as the ability of a body to do work. Energy has the same … Read more

Center of gravity

You must have seen a circus artist doing a tight rope walk. Ever wondered how he manages to walk on a rope without falling down and why he stretches his hands or holds a long bamboo pole while doing so? … Read more


Logarithm – Please recall that you have earlier learnt about indices. One of the results we learnt is that if 2x = 23, X=3 and if 4n = 4y then x = y, i.e., if two powers of the same … Read more

Simple Pendulum

A point connected to a light mass is called a simple pendulum suspended with mass and fixed support. Simple pendulum experiment A simple pendulum consists of a particle of mass ‘m’ usually called bob, suspended from a rigid support with the … Read more

Surface Tension

Surface tension is the property of a liquid rest, due to to which the top surface of a liquid contained in a vessel behaves like a stretched membrane occupying minimum surface area. Surface tension formula t = f/l. Si unit of … Read more


Force can be defined as the physical cause that tends to change the resting position or uniform motion or to change the shape and size of the body. Classification of Forces Forces are classified as contact and non – contact forces. Forces can be applied … Read more


Definition of inertia Inertia – The tendency of an object to resist changes to its state of motion. What is Inertia ? Inertia – This property of the body to continue in its state of rest or uniform motion unless acted upon by … Read more


Sound is a form of energy which causes sensation of hearing. Sound is produced by vibrating bodies. When a bell is struck with a metallic rod, it produces sound. We can sense the vibrations of the bell while it is … Read more


A solution is homogeneous mixture of two or more substances. The proportion of the constituents of the solution can be varied within certain limits. The solutions comprising the two components are called binary solutions.   That component of a solution which is in the same … Read more


Speed definition – Speed is defined as the rate at which a particle covers a distance along a given path. It is given by the ratio of distance travelled to the time taken. Speed formula – Distance travelled (s)/Time (t) Note Since distance travelled is a scalar, the speed of a particle is also a scalar. The unit … Read more