General Science Mixed Quiz: Set 178

In Newton's second law, F = ma, the force on a body is proportional to its acceleration, and the constant linking the two is the body's mass.

In 1796 Edward Jenner used matter from a cowpox sore to protect a boy against smallpox, the first vaccination in the modern sense, and the word vaccine comes from vacca, the Latin for cow.

Work equals force multiplied by displacement, and 4 N multiplied by 0.25 m gives exactly 1 joule.

This soil bacterium naturally transfers a part of its tumour inducing plasmid, called the Ti plasmid, into the cells of a dicotyledonous plant and causes crown gall disease; genetic engineers disarm the plasmid, insert the gene they want and use the bacterium as a vector, which is why it is…

It states that when hot and cold bodies are mixed in an insulated system, heat lost by the hot body equals heat gained by the cold body.

A satellite is given the required height and speed by its launch vehicle, and after that no engine is needed: the gravitational pull of the earth alone acts on it and provides the centripetal force that keeps it in a curved path, so the satellite keeps falling towards the earth…

Air near the ground is denser than air higher up, so sunlight bends as it passes through the atmosphere and reaches us while the Sun is still just below the horizon.

Working on the observations of Tycho Brahe he found that a planet moves in an ellipse with the sun at one focus, that the line from the sun to the planet sweeps equal areas in equal times, and that the square of the orbital period is proportional to the cube…

Oxidising power of the halogens falls as we go down group 17, so iodine is the weakest and fluorine the strongest oxidising agent.

The cerebellum lies behind and below the cerebrum and coordinates voluntary muscular activity, so it keeps the body balanced and the posture steady; damage to it causes a staggering walk even though the muscles are strong.

In a crash a sensor fires an igniter, and sodium azide breaks down almost instantly into sodium and a large volume of nitrogen gas that fills the bag.

The mango belongs to the genus Mangifera and the species epithet indica marks its Indian origin; it is also the national fruit of India, which is why this name appears in both science and static general knowledge papers.

Sodium hydroxide dissolves in water and splits completely into Na+ and OH- ions; the ions carry current and the hydroxide ions make the solution strongly basic.

Phycology, also called algology, is the study of algae, the simple photosynthetic organisms that range from the single-celled Chlamydomonas to the large brown seaweeds, and it covers their classification and their uses as food, fertiliser and a source of agar.

Caesium melts at about 28.5 °C, the lowest of these alkali metals, so it can turn liquid on a warm day or in the hand.

Sugar dissolves in water as whole, neutral molecules and releases no ions, so its solution does not conduct electricity. A solution conducts only when it contains free ions that can carry charge between the electrodes.

This statement is false: diamond is an electrical insulator because it has no free electrons. In diamond, every carbon atom uses all four of its valence electrons to form strong covalent bonds with four other carbon atoms in a rigid three-dimensional network.

Marble, chalk and limestone are all made of the same compound, calcium carbonate, with the formula CaCO3. They differ only in how they were formed.

Parenchyma is the basic packing tissue of plants, and it is also present in both xylem (xylem parenchyma) and phloem (phloem parenchyma).

The gastric glands in the stomach wall secrete pepsin, which begins the digestion of proteins into smaller peptides. The chief cells of the gastric glands release pepsin in an inactive form, pepsinogen.