2. Arrange the following types of electromagnetic waves in order by wavelength, from longest to shortest: Gamma rays, visible light, infrared radiation, ultraviolet radiation, microwaves, radio
waves, X-rays

Radiowaves >  microwaves> Infrared radiation > visible light > Ultraviolet radiation > x -rays > gamma rays

Explanation:

To solve this problem, we use the electromagnetic spectrum as a reference. On the electromagnetic spectrum, the lesser the wavelength, the higher the frequency and more energetic a wave is.

 Therefore;

  Radiowaves >  microwaves> Infrared radiation > visible light > Ultraviolet radiation > x -rays > gamma rays

So, radiowaves have the longest wavelength and gamma rays have the shortest.

speed of light in vacuum is 300,000 km/s

speed of light in other mediums is given by the expression v = c/n, where c is the speed of light in vacuum and n is the refractive index of medium.

for the first medium v = 200,000 km/s

  so, refractive index of medium = 300000/200000 = 1.5

    1.5 refractive index is usually for glass. so first medium is glass.

for the second medium v = 250,00 km/s

so, refractive index of medium = 300000/250000 = 1.2

    1.2 refractive index is usually for water. so second medium is water.

for the third medium v = 0 km/s

so, refractive index of medium = 300000/0 = ∞

    ∞ refractive index is usually for opaque mediums. so third medium is opaque medium.