General Science Mixed Quiz: Set 182

Newton's law of cooling describes a hot body losing heat to cooler surroundings, which is exactly what a cup of coffee on a table does.

Panthera tigris is the tiger, the national animal of India, and the Bengal tiger found in the country is its subspecies Panthera tigris tigris, a three part name that illustrates trinomial nomenclature.

The two pathogens have been swapped: malaria is caused by Plasmodium and TB by Mycobacterium, so both pairs are wrong.

Herpetology is the study of reptiles such as snakes, lizards, crocodiles and turtles, together with amphibians such as frogs, toads and salamanders, and in India it includes the work on snake venom and antivenom at institutions that maintain snake parks.

The green light that chlorophyll does not use is reflected back to our eyes, so leaves look green. White sunlight contains all the colours of the visible spectrum.

Osmosis is the movement of water from a dilute solution to a more concentrated one across a selectively permeable membrane.

For lenses in contact the powers add: 2.5 D + (−2.0 D) = +0.5 D, and the focal length is 1/0.5 = +2.0 metres.

When a wire is stretched its volume stays the same, so the length must grow in the same ratio as the cross-sectional area shrinks.

Tooth enamel is made mainly of calcium phosphate in the form of a hard crystal called hydroxyapatite. Enamel is the hardest substance in the human body, harder even than bone.

Argemone mexicana, the prickly poppy known in India as satyanashi, has seeds that look very like mustard seeds, so its oil is a classic adulterant of mustard oil.

Rubidium, an alkali metal like caesium, gives off electrons easily when light falls on it, so it is used in photoelectric cells.

A rod standing upright on one end falls over at the slightest push, because its centre of gravity is high and its base is tiny.

Dixon and Joly explained that water molecules cling to one another by cohesion and to the xylem walls by adhesion, forming an unbroken column; evaporation from the leaf surface creates a suction at the top that pulls this column upward.

The queen can lay both fertilised and unfertilised eggs; the unfertilised ones develop into haploid males called drones, a form of parthenogenesis, while fertilised eggs give rise to diploid females.

Hooke found that so long as a body is not strained beyond its elastic limit, the restoring force per unit area rises in step with the fractional deformation, and the constant ratio of the two is called the modulus of elasticity.

For a swinging pendulum, the component of the bob's weight along its path always pulls it back towards the lowest point, so gravity acts as a restoring force.

Oxygen in the air reacts with the fats and oils, and the food turns rancid, with a bad smell and taste.

Urea, CO(NH2)2, contains about 46 per cent nitrogen, the highest of any common solid fertiliser, and is the main nitrogen fertiliser used in India.

Egg white is mostly water and protein, and heat denatures these proteins so that they set into an opaque white solid.

The statement is wrong because the inner wall of a thermos flask is silvered so that it radiates very little heat; the shiny outer surface also reflects heat back rather than absorbing it.