General Science GK Questions with Answers – Page 98

The cranial nerves arise from the brain and serve the head and neck, among them the optic nerve of sight, the auditory nerve of hearing, the olfactory nerve of smell and the vagus, which is the longest cranial nerve and reaches down to the heart, lungs and stomach.

Iodine is needed to make thyroxine, so when the diet is short of it the thyroid gland works harder and enlarges into a visible swelling of the neck called goitre; a severe shortage in a growing child causes cretinism and in an adult myxoedema, and iodised salt is the standard…

Insulin lowers the level of glucose in the blood by helping the cells take it in and by having the liver store it as glycogen, and a want of insulin or a failure of the body to respond to it causes diabetes mellitus.

It is called the master gland because its secretions control other glands: thyroid stimulating hormone drives the thyroid, adrenocorticotropic hormone the adrenal cortex, and the gonadotropins the testes and ovaries, besides its own growth hormone.

The correct answer is B, the cerebellum, which lies below and behind the cerebrum and coordinates the work of the muscles so that movement is smooth and the body stays balanced; this is why a person whose cerebellum is affected by alcohol staggers.

The correct answer is B, the thyroid gland, a butterfly-shaped gland in front of the windpipe in the neck, which is the largest purely endocrine gland in the body and secretes thyroxine, triiodothyronine and calcitonin.

The brain is the organ that interprets pain, but its own tissue has no pain receptors, so cutting or pricking it causes no sensation; the covering membranes, the blood vessels and the scalp do have receptors, which is why a headache hurts.

A bacterial flagellum is built of exactly these three parts. The filament is the long thread outside the cell, made of the protein flagellin coiled into a hollow helix, and it acts like a propeller.

Photosynthesis makes carbohydrate and gives out oxygen, and of the four choices here only oxygen is something the plant produces.

Fluorine is the most electronegative element, so in every compound it pulls the shared electrons towards itself and always shows an oxidation number of -1.

The number of moles is the given mass divided by the molar mass, so 60 grams of helium divided by 4 grams per mole gives 15 moles.

A mole is a count, not a weight: one mole of any element holds 6.022 into 10 to the power 23 atoms, the Avogadro number, whatever the element is.

Oil does not dissolve in water; it stays as a separate layer or as floating droplets, so the mixture is heterogeneous and the boundary between the two liquids can be seen.

Reduce the parallel pair first: 20 into 30 divided by 50 gives 12 ohms. Adding the 8 ohm resistor in series makes the circuit resistance 20 ohms, so the battery drives 12 volts divided by 20 ohms, that is 0.6 ampere, through the whole circuit.

In a class 3 lever the effort is applied between the fulcrum and the load, so the effort always sits nearer the fulcrum and its arm is the shorter of the two.

For resistors in parallel the reciprocals add, so one over R equals one over 20 plus one over 20, which is 2 over 20, and R comes out as 10 ohms.

The velocity ratio of a pulley system is the distance moved by the effort divided by the distance moved by the load, so it is 12 divided by 3, that is 4.

Pliers and scissors are each made of two arms joined at one rivet, and each arm is a complete class 1 lever, so the tool is called a double lever.

First find the throwing speed from the height: v squared equals u squared minus 2 g h gives u equal to the square root of 2 into 10 into 80, that is 40 metres per second.

Put the values straight into s equal to u t minus half g t squared, taking upward as positive: 30 into 4 gives 120, half of 10 into 16 gives 80, and the difference is 40 metres.