General Science Mixed Quiz: Set 191

Using v² = u² + 2as with u = 12 m/s, v = 0 and s = 45 m gives a = −144 ÷ 90 = −1.6 m/s².

Brown algae of the class Phaeophyceae contain chlorophyll a and c along with the xanthophyll pigment fucoxanthin, and because fucoxanthin masks the green chlorophyll the plant looks olive green to deep brown; Laminaria, Sargassum, Fucus, Ectocarpus and Dictyota are examples, and many of them bear air bladders that keep the…

Kinetic energy equals p²/2m, so doubling the momentum p makes the kinetic energy four times as large. Momentum is p = mv and kinetic energy is KE = ½mv².

Chlorine released from chlorofluorocarbons destroys ozone fastest where polar stratospheric clouds form in the extreme cold of winter, because those ice clouds hold the chlorine compounds that sunlight then breaks up; the thinning is therefore deepest over Antarctica, where it is called the ozone hole, and is seen over the…

Cotton soaks up sweat well, and as that sweat evaporates from the cloth it takes heat away from the body and keeps us cool.

By mass, an adult human body has the most oxygen, then carbon, hydrogen and nitrogen. Oxygen makes up about 65 percent of body mass, carbon about 18 percent, hydrogen about 10 percent and nitrogen about 3 percent.

Total internal reflection happens only when light inside a denser medium meets the boundary with a rarer one at an angle larger than the critical angle, and all of the light is reflected back.

In a binomial name the first word is the genus and is written with a capital initial letter, while the second word is the species epithet and is written entirely in small letters; both are italicised in print and underlined separately in handwriting.

This statement is false, because sound in air travels as longitudinal waves, not transverse waves. In a longitudinal wave, the particles of the medium vibrate back and forth along the direction in which the wave moves, forming compressions and rarefactions.

Anthropology, from the Greek 'anthropos' (human) and 'logos' (study), is the science of human beings: how societies and cultures began, how they changed and how people live today.

An electric generator converts mechanical energy into electrical energy and so produces electric current. A generator works on electromagnetic induction, discovered by Michael Faraday in 1831.

The velocity ratio is the distance moved by the effort divided by the distance moved by the load, that is ten divided by two point five, which is four.

In 1913 the English physicist Henry Moseley showed that atomic number, not atomic mass, is the fundamental property of an element.

The standard hydrogen electrode has a real, non-zero potential; it is only assigned the value zero by convention. The absolute potential of a single electrode cannot be measured, because any measurement needs a second electrode to complete the circuit.

Silver reacts with sulphur compounds in the air, mainly hydrogen sulphide, and forms a black coating of silver sulphide. This blackening is the tarnishing of silver, a kind of corrosion.

Pasteurisation is not sterilisation: it is a mild heating that kills disease-causing organisms such as Mycobacterium tuberculosis, Salmonella and Brucella and most spoilage bacteria, while leaving the taste and nutritive value of milk largely unchanged.

In graphite each carbon atom is joined to three others in a flat layer of hexagonal rings, like a honeycomb.

Human cells, like all animal cells, have only a flexible plasma membrane on the outside and no rigid cell wall.

Pyruvate, the ion of pyruvic acid (CH3COCOOH), is a three-carbon molecule. It is formed at the end of glycolysis, the first stage of respiration, which takes place in the cytoplasm of every living cell.

It reverses the facts: the pulmonary arteries carry deoxygenated blood and the pulmonary veins carry oxygenated blood. Arteries and veins are named by the direction of flow, not by the oxygen they carry.