General Science GK Questions with Answers – Page 48

On a frictionless surface the person can move only by throwing something out in one direction, and a sneeze pushes air forward so the body recoils backward.

Guttation is the loss of water in the form of liquid droplets from the edges and tips of leaves. Guttation happens mostly at night or early in the morning, when the soil is moist and the air is humid, so transpiration is slow.

In uniform circular motion the speed stays the same, but the direction of the velocity keeps changing, so the car is always accelerating and the direction of that acceleration keeps changing too.

When a candle burns, the wax first melts and turns to vapour, which is a physical change, and the vapour then burns in air, which is a chemical change.

A simple microscope is just a convex (converging) lens of short focal length, held close to the eye, which gives an enlarged image of a small object.

PET fibre (polyester) is blended with wool and cotton, and PET bottles are widely recycled into new products. Polyethylene terephthalate is a polyester made from ethylene glycol and terephthalic acid.

Only pair 3 is right; the descriptions of Cepheids and nebulae have been swapped. Cepheid variables are pulsating stars that brighten and dim on a regular cycle.

All four terms come from physics and cosmology, the study of how the universe and its matter work. An event horizon is the boundary around a black hole beyond which nothing, not even light, can escape.

The magnetic force depends on the sine of the angle between velocity and field, and sin 90° is the largest value.

L4 lies on Earth's orbit 60° ahead of the Earth, so it is as far from the Sun as from the Earth.

The number of protons in the nucleus defines an element, and no two elements share it. The atomic number (Z) is the number of protons in an atom's nucleus, and in a neutral atom it also equals the number of electrons, which decide chemical behaviour.

A transformer heats up because of energy lost inside it: heat from current in the windings and hysteresis loss in the iron core.

Both statements are true, and the airborne spread of the TB bacterium is exactly why crowded places raise the risk.

A true fruit is a ripened ovary and nothing else. After fertilisation, the ovary of a flower develops into the fruit, its wall becomes the pericarp and the ovules inside become seeds.

The English physician showed in 1796 that deliberate inoculation could protect a person against smallpox. Jenner noticed that milkmaids who had caught the mild disease cowpox did not get smallpox.

By Archimedes' principle, the buoyant force equals the weight of the water displaced by the sphere. A fully immersed body displaces its own volume of water, here 2 × 10⁻⁴ m³.

The potato is Solanum tuberosum, and the epithet tuberosum points to the tuber, a swollen underground stem rather than a root, which is the part eaten; the plant belongs to the nightshade family and reached India through the Portuguese.

The lotus, declared the national flower of India, is Nelumbo nucifera, an aquatic plant rooted in the mud of ponds and tanks with leaves and flowers held above the water, and it carries a long place in Indian art and religion.

Turmeric is Curcuma longa, a rhizome of the ginger family whose yellow colour comes from curcumin, and it is well known in the intellectual property story in which a United States patent on the use of turmeric for wound healing was revoked after India produced evidence of traditional knowledge.

Bombyx mori is the mulberry silkworm, the insect reared in sericulture, whose larva spins the cocoon from which mulberry silk is reeled, and the word mori refers to the mulberry on whose leaves it feeds.