General Science Mixed Quiz: Set 94

Soft sand gives way slowly, so the person is brought to rest over a longer time and the force on the body is smaller.

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.

Work is W = F × d × cos θ, and when the angle θ between force and displacement is 90°, cos 90° = 0, so the work done is zero.

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.

As an object comes in from far away towards C, its real, inverted image moves out from the focus towards C, and the two meet at C. For a concave mirror, an object at infinity forms its image at the focus F, and an object at the centre of curvature…

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.

A Mach number greater than 1 means the body is moving faster than sound in the surrounding medium. The Mach number is the ratio of a body's speed to the speed of sound in the medium around it, named after the Austrian physicist Ernst Mach.

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.

The longer wire's resistance works out to 2.88 times that of the shorter one, which is 188% more. Resistance is R = ρL/A, where ρ is the resistivity of the material.

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.

Argon has atomic number 18, and a neutral atom has as many electrons as protons, so it has 18 electrons.

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.

Magnesium ribbon burns in air with a dazzling white flame, giving off heat and light and leaving a white powder of magnesium oxide.

Balance is controlled by the inner ear, which holds the vestibular apparatus alongside the organ of hearing. It is made of three semicircular canals set at right angles to one another and two small sacs, the utricle and the saccule.

Silver and copper are the two best conductors of heat among metals. Metals conduct heat because their free electrons carry energy quickly through the solid.

The anther is the top part of the stamen, the male organ of a flower, and pollen grains form inside it.

Saturated open-chain hydrocarbons are the alkanes, and every alkane fits the formula CₙH₂ₙ₊₂. In a saturated hydrocarbon every carbon atom is joined to others only by single bonds, so each carbon holds the largest possible number of hydrogen atoms.

Soft soaps are potassium salts of fatty acids, while ordinary hard bar soaps are sodium salts. Soap is made by saponification, heating an oil or fat with an alkali.

A bacterium is a prokaryote, so its DNA lies in an irregular region called the nucleoid, with no nuclear membrane around it.

In aerobic tissues, where oxygen is available, glucose is broken down completely into carbon dioxide, water and energy. Aerobic respiration begins with glycolysis in the cytoplasm, which gives pyruvate.