General Science GK Questions with Answers – Page 101

It is a dome-shaped sheet of muscle that separates the chest cavity from the abdomen, and when it contracts it flattens, which increases the volume of the chest, lowers the pressure inside the lungs and draws air in; the intercostal muscles between the ribs assist by lifting the rib cage…

The right lung is divided into three lobes, an upper, a middle and a lower, while the left lung has only two, because the heart is tilted towards the left side of the chest and takes up room there; the left lung even carries a notch called the cardiac notch…

The gastric glands secrete hydrochloric acid, which makes the contents of the stomach strongly acidic; pepsin can work only in such a medium, and the acid also kills most of the bacteria swallowed along with food.

At roughly six to seven metres it is by far the longest part of the nine-metre alimentary canal, it is where digestion is completed by pancreatic and intestinal juices, and its inner wall carries millions of finger-like villi that give a vast surface for absorbing glucose, amino acids, fatty acids…

Bile is made in the liver, stored and concentrated in the gall bladder and poured into the duodenum, and it carries bile salts and bile pigments but not a single digestive enzyme.

It is secreted by the three pairs of salivary glands and breaks starch into the smaller sugar maltose, which is why starch is the only class of food whose digestion actually begins in the buccal cavity.

It is the largest gland as well as the heaviest internal organ of the human body, it lies in the upper right part of the abdomen, and its chief contribution to digestion is bile, which is stored in the gall bladder and emulsifies fat.

Inhalation, also called inspiration, is the phase of breathing in which the diaphragm flattens and the intercostal muscles pull the ribs up and out, so the chest cavity enlarges, the pressure inside the lungs falls below the pressure of the atmosphere and oxygen rich air rushes in through the nostrils…

Mayonnaise is an emulsion: very small droplets of oil are beaten into a watery liquid of egg yolk with vinegar or lemon juice, and the droplets stay spread out instead of separating into a layer.

Stoichiometry is the branch of chemistry that measures how much of each reactant is used up and how much of each product is formed in a reaction, working from the balanced chemical equation.

One mole of any gas occupies 22.4 litres at STP, so 5.6 litres is 5.6 divided by 22.4, that is one quarter of a mole.

Sublimation is the change from solid to vapour without passing through the liquid stage. It happens when particles of the solid gain enough energy to escape straight into the gas phase, and the reverse change, gas to solid, is called deposition.

Only vitamin C and the eight vitamins of the B complex dissolve in water; the rest dissolve in fat.

The B complex is a group of eight water soluble vitamins that work mainly as helpers in the reactions that release energy from food.

Cinnabar is mercuric sulphide, HgS, and the formula itself gives the answer away because Hg is the symbol of mercury.

Muriatic acid is the old trade name for hydrochloric acid, the water solution of hydrogen chloride gas, and the name survives in the market for the crude commercial grade used for cleaning metal and masonry.

Radiation carries heat as electromagnetic waves, so it needs no material medium and can travel through a vacuum. This is how the heat of the Sun crosses empty space to reach the Earth, and why you feel warmth in front of a fire without touching it.

Ethyl alcohol, or ethanol, dissolves resins, gums, dyes and oils and also evaporates quickly, so paints, varnishes and polishes made with it dry fast; this makes it the common solvent of the paint industry.

Ampere-turns per metre, written AT/m, is the unit of magnetic field strength, because H is the magnetomotive force set up per unit length of the magnetic path.

Iodine is the non-metal in the antiseptic painted on cuts and wounds, sold as tincture of iodine, which is a solution of iodine in alcohol.