General Science Mixed Quiz: Set 53

When the ray makes 90 degrees with the surface it is travelling along the normal, so the angle of incidence measured from the normal is zero and the ray goes straight on without bending.

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.

Curium is a radioactive man-made element with the symbol Cm and atomic number 96.

Pisciculture is the rearing of fish in ponds, tanks and other managed waters, the Latin word piscis meaning fish.

Chemical equilibrium is a dynamic state: both reactions go on, but at the same speed, so no net change is seen.

Galileo was the first to argue that, with air resistance removed, every body falls with the same acceleration regardless of its mass.

Methyl ethyl ketone has a methyl group on one side of the carbonyl and an ethyl group on the other, which makes four carbons in all with the carbonyl at the second position, so its IUPAC name is butan-2-one or 2-butanone.

In electroplating the article to be coated is made the cathode, the plating metal serves as the anode, and both are dipped in an electrolyte containing a salt of that metal.

Escherichia coli is a bacterium whose harmful strains reach the body through drinking water or food contaminated with sewage, and the infection they produce shows itself as diarrhoea and abdominal pain, which places it among the classic water-borne illnesses along with cholera, typhoid and hepatitis A. Option A is wrong…

Litmus is a purple dye taken from lichens, and in the classification used in school science lichens are placed in Thallophyta, the group of simple plants whose body is an undifferentiated thallus with no true root, stem or leaf.

In photosynthesis a green plant absorbs sunlight through chlorophyll and uses that energy to join carbon dioxide and water into carbohydrate.

Ultraviolet light is a transverse wave, not a longitudinal one, so this statement is the wrong one. In an electromagnetic wave the electric and magnetic fields vibrate at right angles to each other and to the direction the wave travels, which is the definition of a transverse wave.

A suspension is a heterogeneous mixture because the particles of the solute are large enough to be seen, they do not dissolve, they settle when the mixture is left standing and they can be separated by filtering.

A ligament is the connective tissue that joins one bone to another at a joint. It is very elastic and strong, and it holds the bones in place so that a joint can move without the bones slipping apart.

The principle says a body immersed wholly or partly in a fluid is pushed up by a force equal to the weight of the fluid it pushes aside, and that upward force is called buoyancy or upthrust.

The domestic goat is treated as a subspecies of the wild goat, so its name carries three parts — the genus Capra, the species aegagrus and the subspecies hircus.

Gamma rays are electromagnetic waves of the highest frequency and shortest wavelength, given out by the nucleus of a radioactive atom and in nuclear reactions, and their energy lets them kill cancer cells in radiotherapy.

Bakelite is a thermosetting polymer, made by condensing phenol with formaldehyde, and once it has set under heat its chains are cross-linked, so it cannot be melted and moulded again.

An ordinary incandescent bulb is filled with an unreactive gas, nitrogen usually mixed with argon, so that the white-hot tungsten filament does not burn away.

Capra hircus is the scientific name of the domestic goat, in which Capra is the genus and hircus the species, written in the two-word form that Carl Linnaeus gave to biology.