General Science GK Questions with Answers – Page 122

Before firing, the gun and the bullet are at rest, so the total momentum of the system is zero.

It states that the rate of change of momentum of a body is proportional to the applied force and takes place in the direction of the force.

It is the shortest distance from the starting point to the finishing point together with the direction of that straight line, so it has both magnitude and direction and is therefore a vector.

The first law states that a body continues in its state of rest or of uniform motion in a straight line unless an unbalanced external force acts on it, which is exactly the property called inertia.

Atomicity is the number of atoms in one molecule of an element, and it is why we write nitrogen gas as N2 and not just N. Nitrogen gas exists as N2, two atoms joined by a strong triple bond, so it is diatomic, like oxygen, hydrogen and chlorine.

A hydrogen ion (H+) is just a bare proton, so it cannot stay alone in water. It at once attaches itself to a water molecule and forms the hydronium ion, H3O+.

The inner transition elements are the lanthanides and actinides, in which electrons fill the f-orbitals, so they form the f-block of the periodic table.

The Golgi apparatus is the main site where glycoproteins and glycolipids are formed. It is a stack of flat, disc-shaped sacs called cisternae, first described by Camillo Golgi in 1898.

In DNA, adenine always pairs with thymine through two hydrogen bonds, and guanine pairs with cytosine through three. This is called complementary base pairing, and it is why one strand of DNA can be used to copy the other.

This set is wrong because chikungunya is caused by a virus, the chikungunya virus, and not by bacteria. It is spread by Aedes mosquitoes, the same day-biting mosquitoes that carry dengue and Zika, and it causes high fever with severe joint pain.

The lens of the eye is made mostly of water and special proteins called crystallins, packed in a very regular order that keeps the lens clear so light can pass straight through to the retina.

Plasmodium falciparum causes malignant, or cerebral, malaria, the most dangerous form of the disease. Red blood cells infected by it become sticky and block the small blood vessels of the brain and other organs, which can lead to coma and death if treatment is delayed.

Vitamins A, D, E and K dissolve in fat, while the B group and vitamin C dissolve in water.

The stapedius, only about 1 millimetre long, is the smallest skeletal muscle in the human body. It lies in the middle ear and is attached to the stapes, which is itself the smallest bone of the body.

Monosodium glutamate is the sodium salt of glutamic acid, an amino acid, and it is added to soups, sauces, noodles and snacks to strengthen their savoury taste.

Geitonogamy is the transfer of pollen grains from the anther of one flower to the stigma of another flower on the same plant.

A healthy human ear can hear sound waves with frequencies from about 20 hertz to 20,000 hertz (20 kHz); this band is called the audible range.

Electric current is the rate of flow of electric charge, written as I = Q/t, so one ampere flows when one coulomb of charge passes through a cross-section of a conductor in one second.

Aluminium naturally forms a thin layer of aluminium oxide when it is exposed to air, and this layer protects it from further corrosion.

Haemodialysis uses a machine called an artificial kidney to clean the blood of a patient whose kidneys have failed.