Physics

A dyne is a unit of force in the centimeter-gram-second (CGS) system. It is defined as the force required to accelerate a mass of one gram at a rate of one centimeter per second squared.

As temperature increases, the conductivity of metals decreases because the increased thermal vibrations of the metal ions scatter the conduction electrons more, reducing their mobility.

Charles-Augustin de Coulomb discovered the law of attraction and repulsion between electric charges, formulating Coulomb's law which quantifies the force between charged objects.

Sounds with frequencies below 20 Hz are called infrasonic sounds. This is because the human hearing range typically starts at 20 Hz, so frequencies below this are termed infrasound.

The refractive index is a ratio of the speed of light in vacuum to the speed of light in the medium, making it a dimensionless quantity with no units.

Good absorbents of electromagnetic radiation are also good radiators because materials that absorb energy well tend to emit energy efficiently as well, according to Kirchhoff's law of thermal radiation.

Gamma rays and X-rays are both forms of electromagnetic radiation with very short wavelengths and high energy, making them similar in nature. Alpha (a-rays) and beta (b-rays) rays are particles, not electromagnetic waves, and ultraviolet (U.V.) rays have longer wavelengths and lower energy than gamma rays.

Red light has the longest wavelength among the visible spectrum colors listed, so it is deviated least when passing through a prism or similar medium due to less refraction compared to shorter wavelengths like blue or violet.

Radiation is the transfer of energy through electromagnetic waves and does not require a medium, unlike conduction and convection which require a medium to transfer heat.

The SI unit of force is the Newton, which is defined as the force required to accelerate a one-kilogram mass by one meter per second squared.