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.

General instructions same as in chapter 1. Assertion:Corpuscular theory fails in explaning the velocities of light in air and water. Reason:According to corpuscular theory, light should travel faster in denser medium than in rarer medium.

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 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 instruction same as in chapter 1. Assertion:In two half life of a radioactive sample, all nuclei will decay. Reason:Half life T=(dN)/(dt) .

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 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:A convex mirror cannot form real images. Reason:Convex mirror converges the parallel rays that are incident on it.

General instruction same as in chapter 1. Assertion: The electrostatic force between the plates of a charged isolated capacitro increases, when a dielectric fills whole space between the plates. Reason:The electric field between the plates of a charged isolated capacitor increases, when a dielectric fills the whole space between the plates.

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.

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.