Physics Quiz 6

Danger signs are red because air, water, and dust molecules scatter red light the least. Scattering has an inverse relationship with the fourth power of the wavelength of a particular colour. Because red has the longest wavelength of all the colours, it is the least dispersed.

The main attribute common to all lightning rods is that they are all made of conductive materials, such as copper and aluminium. Copper and its alloys are the most common materials used in lightning protection.

Liquid water has one of the highest specific heat capacities among common substances, about 4184 J⋅kg⁻¹⋅K⁻¹ at 20°C; but that of ice, just below 0°C, is only 2093 J⋅kg⁻¹⋅K⁻¹. Hydrogen gas has more than three times (14300 J⋅kg⁻¹⋅K⁻¹) the specific heat as water under normal laboratory conditions.

An integrated circuit (IC) is a set of electronic circuits on one small flat piece of semiconductor material, usually silicon. IC can function as an amplifier, oscillator, timer, microprocessor, or even computer memory.

A rectifier is a special type of diode that converts alternating current (AC) into direct current (DC).

Asteroids are rocky objects revolving around the sun that are too small to be called planets. The asteroid belt is a torus-shaped region in the Solar System, located roughly between the orbits of the planets Mars and Jupiter.

A capacitor blocks direct current (DC) and allows alternating current (AC) to pass through it. An inductor does not allow AC but allows DC to pass through it. A Diode converts AC into DC. Resistors are used to reduce current flow.

By lowering his hands while catching the cricket ball, the player allows a longer time for momentum change (lower the momentum), thereby preventing his hands from getting injured.

The Special Theory of Relativity is based on Einstein's recognition that the speed of light does not change even when the source of the light moves.

The visible spectrum is the portion of the electromagnetic spectrum that is visible to the human eye. The wavelength of the Visible Light ranges between 380 nm to 750 nm (3800 to 7500 angstroms). (The limits of the visible spectrum are not sharply defined but vary among individuals)