General Science Mixed Quiz: Set 179

The glass of a glowing bulb is heated mainly by radiation from the white-hot filament, not by convection. Conduction passes heat through a solid from particle to particle, convection carries heat by the actual movement of a fluid, and radiation sends heat as electromagnetic waves that need no medium.

Clay is a plastic material: it deforms permanently under even a small force, so its stress is not proportional to its strain.

This is false: aluminium has three electrons in its outer shell and loses all three, so its valency is 3.

A harvested fruit is still a living tissue that keeps respiring, using up its own sugars and acids and giving off heat, carbon dioxide and ethylene.

Sodium hydroxide and hydrochloric acid react to form new substances, sodium chloride and water, so this is a chemical change.

The correct answer is C, Apis dorsata, the rock bee, the largest of the Indian honey bees, which builds a single huge comb on cliffs and tall buildings and yields the most honey per colony, yet is fierce and cannot be kept in hives.

The blue colour comes from water of crystallisation: blue vitriol is CuSO4·5H2O, and heating drives off these five water molecules to leave white anhydrous copper sulphate.

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.

Diamond is an allotrope of carbon, made of carbon atoms alone and nothing else. In diamond each carbon atom is joined to four other carbon atoms by strong covalent bonds, forming a rigid three-dimensional network.

Levers are grouped by where the fulcrum, the load and the effort sit. In a second class lever the load lies between the fulcrum and the effort.

Lysosomes are small sacs bound by a membrane that are filled with digestive enzymes able to break down almost any material in the cell.

Potential difference is the work done to move a unit charge between two points, and its SI unit is the volt.

Fibrinogen is a soluble plasma protein that is turned into insoluble fibrin threads, which form the mesh of a blood clot.

Escape velocity is the minimum speed a body must be given so that it leaves the gravitational pull of the planet and never returns.

The primary structure of a protein is simply the linear order of amino acids joined one after another by peptide bonds.

A red blood cell is a biconcave disc, thin in the middle and thick at the edge, not an amoeboid cell.

Dengue virus is a flavivirus, an RNA (ribonucleic acid) virus of the family Flaviviridae. Dengue is spread mainly by the bite of the female Aedes aegypti mosquito, which breeds in clean, stagnant water and bites during the day.

Cambium lies along the sides of stems and roots and its dividing cells increase their thickness, which is the work of a lateral meristem.

An allele is one of the alternative forms of the same gene, found at the same place on a pair of matching chromosomes.

The Scottish scientist discovered penicillin in 1928 at St Mary's Hospital in London. Fleming noticed that a mould, Penicillium notatum, had accidentally grown on a culture plate of Staphylococcus bacteria and had killed the bacteria around it.