General Science Previous Year Questions (PYQ) with Answers – Page 13

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.

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.

Carbon monoxide reacts with neither acids nor bases to form a salt and water, so it is a neutral oxide.

Taking A as the reference level and ignoring air resistance, all the kinetic energy given at A turns into potential energy at the top, B. Mechanical energy is conserved when only gravity does work.

A chloride XCl 2 means X has valency 2, and an ionic chloride with a high melting point points to a Group 2 metal such as magnesium.

A floating body is in equilibrium, so the upward buoyant force exactly balances its weight. By Archimedes' principle, a body in a liquid is pushed up by a force equal to the weight of the liquid it displaces.

These are the three main divisions of the human brain. The fore brain is the largest part.

Newton's law of gravitation is an independent law of nature; it cannot be derived from his three laws of motion.

The cervix is the lower, narrow neck of the uterus, so it belongs to the female reproductive system. The human male reproductive system has a pair of testes that make sperm and the hormone testosterone.

Rutherford found the nucleus to be positively charged, not neutral. In his gold foil experiment of 1911, Rutherford fired alpha particles at a very thin sheet of gold.

James Chadwick discovered the neutron in 1932, the uncharged particle that sits in the nucleus alongside the proton. Chadwick bombarded beryllium with alpha particles and found that it gave off a penetrating radiation of neutral particles with a mass almost equal to that of a proton.

Among the four, microwaves lie farthest towards the long-wavelength end of the electromagnetic spectrum. In order of increasing wavelength the spectrum runs: gamma rays, X-rays, ultraviolet, visible light, infrared, microwaves and radio waves.

The work done against gravity is mgh = 50 × 10 × 8 = 4,000 J, and doing it in 10 s needs 4,000 ÷ 10 = 400 W. Power is the rate of doing work, P = W/t, and its SI unit is the watt (1 W = 1…

TB spreads through the air when an infected person coughs, sneezes or speaks and others breathe in the tiny droplets carrying the bacteria.

With the velocity changing steadily from 5 m/s to 7 m/s, the average velocity is 6 m/s, and 6 m/s × 3 s = 18 m. For uniform acceleration, displacement s = ((u + v)/2) × t. Here u = 5 m/s, v = 7 m/s and t = 3…

This is the taxonomic hierarchy for animals, going from the broadest group down to the most specific. Linnaeus built this ladder of ranks, and each rank contains one or more ranks below it.

Each statement says "no virus can", and each is disproved by well-known viruses.

An electron's mass is about 1/1836 of a proton's, which is roughly 1/2000. The electron has a mass of about 9.1 × 10⁻³¹ kg, while the proton has about 1.67 × 10⁻²⁷ kg, nearly 1,836 times heavier.

SONAR uses sound waves under water to find the distance and direction of objects. A SONAR set on a ship has a transmitter that sends out pulses of ultrasound and a detector that picks up their echo from the sea bed, a shoal of fish, a wreck or a submarine.

In a micelle it is the long hydrocarbon tail that points into the oil droplet, while the ionic end faces outward into the water, so statement D reverses the real picture.