General Science Mixed Quiz: Set 122

Sound in air is a longitudinal wave, and only transverse waves can be polarised. Polarisation means restricting the vibrations of a wave to a single plane.

The 2011 FSSAI labelling rules made the list of ingredients, nutrition information and the vegetarian or non-vegetarian mark compulsory, but not medical advice on allergies.

Reversing the pole that approaches the loop reverses the change in magnetic flux, so the induced current reverses too. When a magnet moves towards a closed loop, the magnetic flux through the loop changes and an electric current is induced (Faraday's law of electromagnetic induction).

Meiosis halves them in the gametes, and fertilisation restores them in the offspring. Each parent makes gametes by meiosis, so a human egg or sperm carries 23 chromosomes instead of 46.

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.

The candela takes its name from the candle, which was once used as a rough standard of light, and it is one of the seven base units of the SI system.

Sucralose is made from ordinary table sugar, sucrose, by changing its molecule. In making sucralose, three hydroxyl (OH) groups of the sucrose molecule are replaced by chlorine atoms.

A planimeter measures the area of any flat shape, however irregular its outline. The user simply traces the boundary of the shape on the map with the instrument's pointer, and a wheel and dial record the area swept, which is then multiplied by the square of the map scale.

The enzyme that makes most of the cell's ATP, ATP synthase, sits in the inner mitochondrial membrane along with the electron transport chain.

Carbon-14 is the radioactive isotope of carbon used for radiocarbon dating, and its half-life is close to 5,700 years, which is the figure quoted in the question.

The pituitary is a single, pea-sized gland at the base of the brain, while the other three come in pairs.

Silk is the protein fibroin, spun by the silkworm, so it is a polymer made by a living organism and is therefore natural, like cellulose, starch, wool and natural rubber.

AIDS is caused by HIV, a retrovirus whose genome is two copies of single-stranded RNA. After HIV enters a helper T-cell (CD4 cell), its enzyme reverse transcriptase copies the viral RNA into DNA, which is then built into the host cell's own DNA.

Robert Harding Whittaker proposed the five kingdoms Monera, Protista, Fungi, Plantae and Animalia in 1969, using cell structure, body organisation, mode of nutrition, reproduction and evolutionary relationships as the criteria of division.

Intercalary meristem lies between mature tissues, at the base of leaves and of internodes. Meristems are tissues whose cells keep dividing.

The polymerase chain reaction repeats three steps, denaturation at a high temperature, annealing of short primers and extension of the new strand, so the enzyme must survive near boiling water; Taq polymerase, obtained from the bacterium Thermus aquaticus of hot springs, does exactly that and lets a single DNA segment…

A mutation is a change in the sequence of the DNA or RNA that carries a virus's genes. A virus is made of genetic material, either DNA or RNA, inside a protein coat.

Benzene and water do not mix, so they form two layers that a separating funnel can draw off one after the other.

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.

The eye adjusts the focal length of its lens to bring both near and far objects into focus on the retina, and this ability is called accommodation.