General Science Mixed Quiz: Set 96

Light that enters a cut diamond is reflected again and again inside it before it escapes, which makes the stone sparkle.

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.

A wave carries energy from one place to another, while the particles of the medium only vibrate about their fixed positions.

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.

Electric power is P = V × I, and 220 V × 0.6 A = 132 W. Power is the rate at which electrical energy is used, measured in watts; one watt is one joule per second, or one volt times one ampere.

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.

Magnesium, calcium and barium are all alkaline earth metals of group 2, and each has a valency of 2. Elements in the same group of the periodic table have the same number of electrons in their outermost shell, and so the same valency.

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.

Lithium is so light that it floats on kerosene or paraffin oil, so it is kept coated in petroleum jelly or paraffin wax, or under an inert gas, instead of under oil.

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.

Both are stored forms of glucose, but plants store it as starch and animals as glycogen. Starch and glycogen are polysaccharides, long chains of glucose units.

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.

When blood glucose is more than the body needs, the hormone insulin helps convert it into glycogen, which is stored mainly in the liver and the muscles.

Moving a substance from low to high concentration is uphill work, and the cell pays for it with ATP.

Elephantiasis, or lymphatic filariasis, is an endemic disease: it stays steadily present in certain regions and develops slowly over years, rather than breaking out suddenly in a large number of people.

Hooke's law holds only as far as the limit of proportionality, and that limit is either equal to or lower than the elastic limit, so statements 1 and 4 are the correct pair.

In photosynthesis, green plants take carbon dioxide from the air and combine it with water, using sunlight, to make carbohydrates such as glucose.

Photo 51 is the X-ray diffraction photograph of DNA that revealed its helical shape. The picture was taken in May 1952 at King's College London by Rosalind Franklin and her student Raymond Gosling.

An atomic clock keeps time by locking onto the fixed frequency of radiation that makes atoms such as cesium-133 or rubidium jump between two energy levels.

Mercury(II) oxide is a red-orange solid, mercury is a liquid metal at room temperature, and oxygen is a gas. This is a thermal decomposition reaction: when mercuric oxide is heated, it breaks down into mercury and oxygen, written with states as 2HgO(s) → 2Hg(l) + O₂(g).