General Science Mixed Quiz: Set 183

It occurs through pores called hydathodes at the leaf margin or tip, usually in the early morning when the soil is moist, the air is humid and transpiration is low, so root pressure forces out drops of water with dissolved salts; Colocasia, grasses and tomato show it well.

A beam seen from the side is visible only because tiny particles send some of its light sideways. Light travelling in a straight line cannot enter our eyes unless something redirects it towards us.

Stress is the restoring force divided by the area over which it acts, so its unit is the newton per square metre, and that combination is given the special name pascal, the same unit used for pressure.

A rise of 27°C is a rise of 27 K, because one degree Celsius and one kelvin are exactly the same size.

Its sieve tubes, helped by companion cells, carry sucrose and other soluble food from a source such as a mature leaf to a sink such as a root, fruit or bud, and the movement can be upward or downward.

Pascal's law states that pressure applied to an enclosed fluid is transmitted undiminished in every direction to all parts of the fluid and to the walls of the container.

Strain is defined as the change in a dimension divided by the original value of the same dimension, a length divided by a length or a volume divided by a volume, so the units cancel and only a pure number survives.

It quickens the heartbeat, raises the blood pressure, widens the air passages, sends more blood to the muscles and releases glucose from the liver, so that the body is ready to fight or to run.

In light, potassium ions are actively pumped into the guard cells, their solute concentration rises, water enters by osmosis, the cells swell and because their inner walls are thicker they bend apart, opening the pore; when potassium leaves, the cells lose water and the pore closes.

Kwashiorkor is caused by a severe lack of protein in the diet, even when the child gets some calories from starchy food.

It governs the stretching or compression of a wire or rod along its length and is obtained by dividing the force per unit area of cross section by the fractional change in length.

Bose designed the crescograph to magnify the growth of a plant many thousand times and record it on a smoked glass plate, which allowed him to show that plants respond to light, heat, touch and other stimuli in ways that resemble responses in animals.

Ganong's potometer and the simpler bubble potometer measure the water absorbed by a cut shoot in a given time, and since almost all of that water is lost as vapour, the reading is taken as the rate of transpiration.

An LED is a p-n junction diode that gives out light when current flows through it in the forward direction.

The bulk modulus measures how strongly a substance resists a change in volume under uniform pressure, so its reciprocal measures how readily the volume yields, and that quantity is called compressibility.

Petrol and kerosene are lighter than water and do not mix with it, so water poured on an oil fire sinks below the burning layer and carries it outwards, enlarging the fire instead of putting it out.

Glycolysis, also called the Embden Meyerhof Parnas pathway, splits one molecule of glucose into two molecules of pyruvic acid in the cytoplasm, needs no oxygen and gives a net gain of two ATP along with two molecules of reduced NAD.

Elasticity in physics is not the ability to stretch far but the strength of the restoring tendency, measured by the stress needed to produce a given strain, and steel demands an enormously greater stress than rubber for the same fractional extension.

Pyruvic acid formed in glycolysis enters the mitochondrion, is converted to acetyl coenzyme A and is oxidised completely in the matrix through the cycle named after Hans Krebs, who received the Nobel Prize for the discovery; the cycle releases carbon dioxide and reduced coenzymes.

When a wire is pulled it lengthens and at the same time grows thinner, and Poisson's ratio records how large the sideways contraction is compared with the lengthwise extension; it is a pure number, with theoretical limits of minus one and one half and practical values of about 0.2 to…