General Science Mixed Quiz: Set 17

The work done against gravity is mgh = 40 × 10 × 5 = 2000 joule, and power is work divided by time, so 2000 ÷ 4 = 500 watt.

The name itself says so: in Greek arthros means jointed and podos means foot, so arthropods are the animals with jointed legs.

In 1798 Cavendish used a delicate torsion balance to measure the extremely small attraction between lead spheres in a laboratory and from it obtained a value of G, about 6.674 times ten to the power minus eleven newton metre squared per kilogram squared.

The zygote divides as it travels down the fallopian tube and the resulting ball of cells gets implanted in the thick lining of the uterus.

The efficiency of an ideal Carnot engine is one minus the ratio of the sink temperature to the source temperature, both in kelvin.

Solder is an alloy of lead and tin, usually in nearly equal parts. An alloy is a mixture of a metal with one or more other elements, made to gain a property the pure metal lacks.

The pressure at a point inside a liquid equals the depth multiplied by the density of the liquid and by the acceleration due to gravity.

Algae belong to Thallophyta, the simplest division of the plant kingdom. Their body is a thallus, which means it is not divided into root, stem and leaf, and they have no vascular tissue.

A cooker is sealed, so the steam it produces cannot escape and the pressure inside rises. Since the boiling point of a liquid rises with the pressure on it, water in a cooker boils well above a hundred degrees Celsius, and food cooking at that higher temperature is ready sooner.

An iron rod is a solid, and the force of attraction between particles is strongest in the solid state. In a solid the particles sit close together in fixed positions and can only vibrate, so a solid keeps its shape, has a definite volume and can hardly be compressed.

In orbit the gravitational pull of the earth is the very force that keeps the craft curving around the planet, and the craft, the astronaut and everything inside accelerate towards the earth at the same rate.

Boron has three electrons in its outermost shell, so it is a trivalent element and is used as a p-type dopant.

An adiabatic change is one in which no heat is exchanged with the surroundings.

It states that the upthrust on a body dipped fully or partly in a fluid equals the weight of the fluid the body pushes aside.

Absolute pressure is counted from the absolute zero of pressure, which is a perfect vacuum, so it can never be negative.

A pyrometer measures very high temperatures, such as those of furnaces, kilns and molten metal, without touching the hot object.

If each length of a solid grows by a certain small fraction when it is heated, an area, which is the product of two lengths, grows by about twice that fraction, and a volume, the product of three lengths, by about three times.

A floating body is at rest, so the upward buoyant force must exactly balance the downward weight of the object.

Atmospheric pressure at sea level is about 1.013 into 10 to the power 5 pascal, which presses with roughly the weight of one kilogram on every square centimetre of our body, so it is very large and not negligible at all.

Pressure is the force acting on unit area, that is P equals F divided by A, so for the same force a larger area of contact means smaller pressure.