General instructions same as in chapter 1.
Assertion:Large angle scattering of alpha particle led to the discovery of atomic nucleus.
Reason:Entire positive charge of atom is concentrated in the central core.

General instruction same as in chapter 1. Assertion: Electrons move away from a low potential to high potential region. Reason:Because electrons has negative charge.

General instructions same as iin chapter 1. Assertion:A bar magnet exerts a torque on itself due to its own field. Reaons: Magnetic field due to a magnet is uniform.

General instructions same as in chapter 1. Assertion: An atom has equal number of electrons and protons. Reason:In an atom there are equal number of electrons, protons and neutrons.

General instructions same as in chapter 1. Assertion:An electron jumps from lower to higher orbit in an atom. Reason:The electron absorbs energy to jump from lower to higher orbit.

Given instructions same as in chapter 1. Assertion:Radio waves can be polarised. Reason:Sound waves in air are longitudinal in nature.

General instructions same as in chapter 1. Assertion:Rydberg's constant varies with mass number of a given element. Resaon:The reduced mass of the electron is dependent on a given element.

General instructions same as in chapter 1. Assertion:Bohr had to postulate that electrons in the stationary orbts around the nucleus do not radiate. Reason:According to classical physcis all moving electrons radiate.

Given instructions same as in chapter 1. Assertion:Ultraviolet radiations are of higher frequency waves are dangerous to human beings. Reason:Ultraviolet radiations are absorbed by the atmosphere.

General instruction same as in chapter 1. Assertion: No interference pattern is detected when two coherent sources are infinitely close to each other. Reason:The Fringe width is inversly proportional to the distance between the two slits and a singel fringe may occupy the whole screen.