General Science GK Questions with Answers – Page 96

Bacillary dysentery, also called shigellosis, is caused by bacteria of the genus Shigella, which invade the lining of the large intestine and produce frequent stools with blood and mucus, along with fever and cramps; it spreads through contaminated water and food.

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…

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

Milk is an emulsion because it is tiny drops of liquid fat spread through water, and an emulsion is a colloid in which one liquid is dispersed in another liquid.

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.

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.

Newcastle disease is called Ranikhet disease in India because the first serious outbreak in the country was reported from Ranikhet in the Kumaon hills, while the name Newcastle comes from Newcastle upon Tyne in England, where it was identified in 1926.

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.

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.

A catalytic poison is a substance that lowers or destroys the activity of a catalyst, usually because it sticks firmly to the active surface and leaves no room for the reactants.

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.

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

Charles’s law says that at constant pressure the volume of a fixed mass of gas is directly proportional to its absolute temperature, so V by T stays constant.

Coulomb’s law gives the force between two point charges at rest. It states that the force is directly proportional to the product of the two charges and inversely proportional to the square of the distance between them, and acts along the line joining them.

In the SI system the prefix femto, written f, stands for 10 raised to minus 15. The name comes from the Danish and Norwegian word femten, meaning fifteen.

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

The petiole is the stalk that joins a leaf blade to the stem; it belongs to the leaf, not to the flower, and a leaf without one is called sessile.

Potassium permanganate is a neutral compound, so the oxidation numbers of all its atoms must add up to zero. Potassium, an alkali metal, is always +1, and each of the four oxygen atoms is -2, giving the oxygens a total of -8.

Coulomb friction, also called dry friction, is the resistance that acts when two solid surfaces touch each other with no lubricant between them.

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.