General Science Previous Year Questions (PYQ) with Answers – Page 43

The peacock is a bird, and all birds, like mammals, have a heart of four chambers: two atria and two ventricles.

Zinc has atomic number 30, which means each of its atoms carries 30 protons in the nucleus.

It states that the upthrust on a body dipped fully or partly in a fluid equals the weight of the fluid the body pushes aside.

Atomicity is the number of atoms in one molecule of an element, and it is why we write nitrogen gas as N2 and not just N. Nitrogen gas exists as N2, two atoms joined by a strong triple bond, so it is diatomic, like oxygen, hydrogen and chlorine.

The inner transition elements are the lanthanides and actinides, in which electrons fill the f-orbitals, so they form the f-block of the periodic table.

All three are genetic disorders, caused by changes in genes or chromosomes and passed on through birth, not by germs.

Air always moves from a region of higher pressure to one of lower pressure, so it flows out of the lungs only when the pressure inside them rises above that of the outside air.

Magnification is a ratio of two lengths, so the units cancel and it is a pure number. For a mirror or a lens, magnification m equals the height of the image divided by the height of the object (h′/h).

A ray that passes through the optical centre of a thin lens comes out in the same direction, without any bending.

Red cabbage is a natural acid-base indicator, methyl orange is a synthetic acid-base indicator, and onion and clove are olfactory indicators.

Mercury (Hg) belongs to group 12, not group 11. Group 11 of the modern periodic table holds copper (Cu, atomic number 29), silver (Ag, 47) and gold (Au, 79).

Platelets are the tiny cell fragments that rush to a cut and start the clot. They are also called thrombocytes and are made in the bone marrow from large cells called megakaryocytes.

A qubit, short for quantum bit, is the basic unit of information in a quantum computer.

The symbol of potassium is K, from its Latin name kalium; Po is the symbol of polonium, the radioactive element discovered by Marie Curie in 1898 and named after Poland.

Its chemical name is sodium hydrogen carbonate and its formula is NaHCO3. It is a mild, non-corrosive base made by the Solvay process, in which brine is treated with ammonia and carbon dioxide.

Both pairs are wrong. Amyloplasts store starch, a carbohydrate, and aleuroplasts store proteins; oils and fats are stored by elaioplasts.

Ammonia is NH3, so one nitrogen atom of mass 14 is joined to three hydrogen atoms of mass 1 each, giving 14: 3 by mass.

This is Kirchhoff's first law, the current law or junction rule, which he stated in 1845. It says the total current entering a junction equals the total current leaving it, because charge cannot pile up or vanish at a point.

Kwashiorkor is caused by a severe lack of protein in the diet, even when the child gets some calories from starchy food.

For a lens, magnification m is the image height divided by the object height, which also equals v divided by u. A plus sign means the image is erect and virtual, and a value of 2 means it is twice as tall as the object.