General Science Mixed Quiz: Set 98

Ultrasound is sound with a frequency above 20,000 Hz, the upper limit of human hearing. Humans hear sound between about 20 Hz and 20 kHz.

Above the threshold, the kinetic energy of the ejected electrons rises as the frequency of the light rises, so the statement that it does not change is wrong.

Mitochondria are membrane-bound organelles, and only eukaryotic cells have membrane-bound organelles. Prokaryotes such as bacteria and cyanobacteria have no true nucleus and no membrane-bound organelles; their DNA lies in a region called the nucleoid, and they carry out respiration on their plasma membrane.

Red biotechnology is the branch applied to medicine and health care, including the making of insulin, antibiotics and vaccines. Biotechnology is often divided by colour according to its field of use.

A telescope's objective must gather as much light as possible from a distant object and form a large image, so it is both wide and of long focal length.

A beam seen from the side is visible only because tiny particles send some of its light sideways. Light travelling in a straight line cannot enter our eyes unless something redirects it towards us.

Pitchblende, or uraninite, is the chief ore of uranium, the fuel used in most nuclear power stations. Pitchblende is a heavy, black mineral made mostly of uranium oxide.

Rotational kinetic energy is ½Iω², and the ring has the larger moment of inertia. For a thin ring about the axis through its centre and perpendicular to its plane, all the mass sits at distance R, so I = MR².

Traditional solder is an alloy of lead and tin, often in a ratio of about 60 parts tin to 40 parts lead.

Together the two resins take out every dissolved ion, which leaves demineralised water. In the cation exchange resin (written RH), metal ions such as Ca2+, Mg2+ and Na+ are swapped for H+ ions.

Propane is a light gaseous hydrocarbon that burns completely with a blue flame, leaving no smoke, soot or ash. A clean fuel burns completely, gives high heat and releases few pollutants.

HIV infects and destroys helper T lymphocytes, the white blood cells that coordinate the body's immune response, so immunity steadily collapses.

All three are fungi that feed saprophytically: they release enzymes onto dead organic matter, digest it outside their bodies and then absorb the dissolved food.

Ashwagandha, whose botanical name is Withania somnifera, is called winter cherry in English because of the small red berry it bears inside a papery cover; it is also called Indian ginseng.

Holothuria, the sea cucumber, is an echinoderm, a non-chordate group, so it never has a notochord at any stage of life.

Jupiter is a planet; it does not make its own light and shines only by reflecting sunlight. A luminous object produces light of its own, as stars do by nuclear fusion in their cores, where hydrogen is turned into helium.

The great majority of plant viruses carry their genes as single-stranded RNA. Viruses contain either DNA or RNA, never both, wrapped in a protein coat.

In the sliding filament theory of contraction, a nerve impulse causes calcium to be released from the sarcoplasmic reticulum; the calcium exposes binding sites on the thin actin filaments, the heads of the thick myosin filaments attach to them and swivel, using energy from ATP, and the actin is pulled…

The amendment of 2021 kept termination up to twenty weeks on the opinion of one registered medical practitioner, allowed it between twenty and twenty-four weeks for certain categories of women such as survivors of rape or incest on the opinion of two practitioners, and removed the upper limit where a…

The correct answer is A, Karl Landsteiner, the Austrian physician who found in 1900 that human blood falls into groups according to the antigens on the red cells, which made safe transfusion possible, and who received the Nobel Prize in Physiology or Medicine for it in 1930; with Wiener he…