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.

Which type of mirror can form a real image?

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: 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.

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 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.