Questions

In a chemical reaction, substances (elements or compounds) called reactants are changed into other substances (compounds or elements) called products. Hence, reactants are those which start the chemical reaction.

For example:

1. In the burning of natural gas, methane (CH4) and oxygen (O2) are the reactants in the chemical reaction. are the substances formed by a chemical reaction. In the burning of natural gas, carbon dioxide (CO2) and water (H2O) are the products formed by the reaction.

2. H2+O2 ----> H2O

Here H2 & O2 are called Reactants and H2O is called Product.

To evaporate the water that oozes out, heat is required. Part of this heat is taken from the water inside which therefore become cool. Therefore (C) is correct. Here evaporation is less, so cooling too is less.

Number of spectral lines from a state n to ground state is

                   n(n-1)/2 = 6

The book “Indira Gandhi – A life in Nature”, was launched by Congress president Sonia Gandhi at the Indira Gandhi Memorial in the presence of former ministers, bureaucrats and environmentalists who worked closely with her to frame some of country’s landmarks wildlife and environment laws. Renowned mountaineer Capt Manmohan Singh Kohli recalled how Gandhi once told him “please call me as a daughter of the mountains”. The book has been written by former Union minister Jairam Ramesh and it has been published by Simon & Schuster.

World Press Freedom Day is observed on 3 May every year.

This year’s theme is “Critical Minds for Critical Times: Media’s role in advancing peaceful, just and inclusive societies”.