General Science GK Questions with Answers – Page 77

Hypobromous acid has one hydrogen, one oxygen and one bromine atom, with bromine in the +1 oxidation state. The oxyacids of a halogen are named by how much oxygen they hold.

Field lines always leave a conductor normal to its surface, and for a positive charge they point away from it.

Buckminsterfullerene is C60, a cage-shaped molecule of sixty carbon atoms. The sixty atoms are arranged in 12 pentagons and 20 hexagons, the same pattern as the panels of a football, which is why the molecule is also called a buckyball.

The eye changes the focal length of its lens to focus and changes the size of its pupil to control the light.

Diffusion is the spontaneous mixing of the particles of two substances, caused by the constant motion of those particles. Particles of matter are always moving and have spaces between them.

Gravity is a conservative force, so the work it does never depends on the path. The work done by gravity on a body of mass m is mgh, where h is the vertical height between the start and the end.

On the magnetic equator the angle of dip is zero, so the Earth's magnetic field there is entirely horizontal. The Earth behaves like a huge bar magnet.

In a uniform field the two poles of the magnet feel equal and opposite forces, which cancel each other.

Momentum is a vector, and on bouncing the ball's direction of motion reverses at once, from downward to upward. Just before impact the ball moves down with velocity v, so its momentum is mv downward.

Friction acts only where two surfaces touch, while a magnet can push or pull an object across a gap. Forces are grouped by whether the bodies must touch.

Each piece has a resistance of 10 ohm, and five equal 10-ohm resistors in parallel give 10 ÷ 5 = 2 ohm.

Steel is an alloy of iron with a small amount of carbon, and carbon is a non-metal. Ordinary steel carries roughly 0.05 to 2 per cent carbon.

One kelvin and one degree Celsius are the same size, so a rise of 30 K is also a rise of 30°C. The Kelvin and Celsius scales differ only in their starting point: T(K) = t(°C) + 273 (more exactly 273.15).

Work done by gravity depends only on the difference in potential between the two points, and here that difference is zero.

Only the gravitational field of a spherical body and the electrostatic field of a point charge fall off as 1/r².

High pressure pushes the gas molecules close together and low temperature slows them down, so the attractive forces can hold them as a liquid.

Jupiter is a planet; it does not make its own light and shines only by reflecting sunlight. A luminous object produces light of its own, as stars do by nuclear fusion in their cores, where hydrogen is turned into helium.

The liver cells (hepatocytes) are rich in smooth endoplasmic reticulum, whose enzymes break down drugs, alcohol and poisons into harmless forms.

Red biotechnology is the branch applied to medicine and health care, including the making of insulin, antibiotics and vaccines. Biotechnology is often divided by colour according to its field of use.

The triple point is the single temperature and pressure at which the solid, liquid and vapour phases of a substance exist together in equilibrium.