General Science Mixed Quiz: Set 3

The newton is a derived unit: it is built from the kilogram, the metre and the second, since force equals mass times acceleration, and it can be written as one kilogram metre per second squared.

In diamond every carbon atom is joined to four other carbon atoms by strong covalent bonds. These bonds point towards the corners of a tetrahedron and build a rigid three-dimensional network that runs through the whole crystal.

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

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.

It gives the direction of the force, and so of the motion, on a current-carrying conductor placed in a magnetic field, which is exactly what turns the coil of a motor.

Beriberi is caused by a lack of thiamine, which is vitamin B1. Thiamine helps the body turn carbohydrates into energy and keeps nerves and the heart working, so its shortage weakens muscles and nerves (dry beriberi) or causes swelling and heart failure (wet beriberi).

Period 2 holds the eight elements from lithium (3) to neon (10), and group 17 is the halogen column, whose members have seven electrons in the outer shell.

Of the three, only citrus canker is caused by bacteria; rust of wheat is caused by a fungus and yellow vein mosaic of bhindi by a virus.

Water is called the universal solvent because its molecule is polar: the oxygen end carries a partial negative charge and the two hydrogen ends carry partial positive charges.

It is the main growth inhibitor among plant hormones and works against the growth promoters.

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

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

Aluminium oxide and zinc oxide behave like a base with acids and like an acid with bases, so both are amphoteric.

At great heights the air is thin, so the atmospheric pressure acting on the body is much lower than at sea level.

Calcium oxychloride (CaOCl2) is bleaching powder, and the chlorine it releases removes colour from cotton and linen in the textile industry.

A healthy human ear can hear sound waves with frequencies from about 20 hertz to 20,000 hertz (20 kHz); this band is called the audible range.

The nucleus is called the master or control centre of the cell because it directs all the activities of the cell.

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.

The pituitary gland sends out hormones that order the thyroid and the adrenal glands to release their own hormones. The pituitary is a pea-sized gland attached to the base of the brain, and it is called the master gland because it controls several other endocrine glands.

Vitamins fall into two groups: the water-soluble ones, which are vitamin C and the whole B-complex, and the fat-soluble ones, A, D, E and K. Vitamin C is ascorbic acid, found in citrus fruits, amla, guava and tomatoes; its deficiency causes scurvy, with bleeding gums and slow healing of wounds.