Part-B (General Ability) NDA/NA Solved Paper 2017-I

Iron corrodes rapidly, because of its non-stable corrosion products on the surface. Rust occurs when metals containing iron react with the oxygen in the air or in water and form acompound called iron(III) oxide
(ferric oxide). This compound contains water molecules, so we call it a hydrated compound.
Both oxygen gas and water must be present for the iron to rust. Chemically and very simply speaking, iron atoms lose
a few electrons to oxygen atoms. This process by which electrons are removed from atoms is called oxidation. When oxidation occurs, it produces a chemical reaction that creates iron(III) оxide-or rust.

Mass of solute (salt) =20g
Mass of solvent (water) = 180g
Mass of solution = 20+180=200g
Concentration = mass of solute/mass of solution x 100
=20 × 100/200=2000/200= 10%

Valency is the measure of the combining capacity of atoms or molecules. Therefore, it is the capacity of an atom of a single element to react and combine with particular numbers of atoms of another element. The
electrons present in the outermost shell/orbit of an atom are called valence electrons. The valence electrons take part in any chemical reaction because the outermost orbit usually contains more energy than the electrons present in other orbits. The valency of an element
depends upon the total number of electrons in the outer most shell of an atom.

Cone cells, or cones, are photoreceptor cells in the retinas of vertebrate eyes (e.g. the human eye). They respond differently to light of different wavelengths, and are thus responsible for color vision and function
best in relatively bright light, as opposed to rodcells, which work better in dim light.

Proteins are biological macromolecules that are diverse in shape size and function. Proteins is the larger set of molecules to which enzymes belong as subsets. Therefore All proteins are not enzymes but mostly enzymes are proteins.

Sugarcane is generally grown to obtain sucrose.

Marigolds are hardy, annual plants and are great plants for cheering up any garden. Broadly, there are two genuses which are referred to by the common name, Marigolds viz. Tagetes and Celandula. The colourful part of Marigold is Inflorescences. These are clusters of flowers on a branch or a system of branches. They are categorized generally on the basis of the timing of their flowering and by their arrangement on an axis.

Orissa is the largest producer and produces over 37% manganese ore ore of India. Rajasthan is by far the largest producer of gypsum in India and it produces almost 99% of the total production Gypsum in India. Major deposits of magnesite are found in Uttaranchal.

The given national parks, Corbett, Sariska, simlipal and Periyar are situated at Uttarakhand, Rajasthan, Odisha and Kerala respectively.