Given the above information, and given that solids generally have greater optical densities than liquids, and that liquids generally have greater optical densities than gases, which of the following statements is true?the number of wavelengths per unit time will not change as a light wave moves from a solid into a liquid.

Optical density is defined as the ratio of speed of light in air with speed of light in any given medium

so it is given as

now we have as per above equation

speed of light = frequency * wavelength

so we can write

and also

so the frequency of light will not change as we move from one medium to another medium.

As per above equation we can also write

when insulating materials rub against each other, they may become electrically charged . electrons , which are negatively charged, may be 'rubbed off' one material and on to the other. the material that gains electrons becomes negatively charged. the material that loses electrons is left with a positive charge.

the earths atmosphere is made up of nitrogen and oxygen. solids can turn into gasses through a process called sublimation. sublimation is the transition of a substance directly from the solid to the gas phase, without passing through the intermediate liquid phase.

hope this : d