What refers to the bending of light as it passes from one medium into another? 10. Which of the following arrangements of visible light colors shows decreasing wavelength?
A. red, orange, yellow, green, blue, indigo, violet
B. red, yellow, green, orange, violet, blue, indigo
C. violet, blue, green, orange, red, indigo, yellow
D. violet, indigo, blue, green, orange, yellow, red

12. What refers to the splitting of white light into seven different colors?

A. dispersion
B. refractive index

C. reflection
D. refraction

13. Refractive Index is a ratio between the speed of light in vacuum and .

A. speed of light in vacuum
B. speed of sound in vacuum

C. speed of light in a medium
D. speed of sound in a medium

15. Based on the colors of light, what color comes between red and yellow?

9.Refraction

13.refractive index is the ratio of velocity of light in a vacuum to it's velocity I. a specified medium.

12.dispersion

14.Orange with a wavelength of about 585-620

I have no idea of number 10

scattering of light by tiny particles in air to produce the colors we see on sky, is dependent on the following factors:

(i) wavelength of light

(ii) size of the scattering particle  

(iii) distance traveled by light through the atmosphere.

according to rayleigh's law of scattering, the amount of scattering is inversely proportional to the fourth power of its wavelength. shorter the wavelength, greater is its scattering. hence violet/blue light is scattered more than red.

sun's light is a composite light ( visible light) with wavelengths in the range 400 nm (violet) to 700 nm (red). as sunlight passes through our atmosphere, the molecules of air scatter light according to their wavelengths. during sunrise and sunset, the sun's position is below the horizon. hence light from the sun travels a greater distance in the atmosphere when compared to its position a noon.

as sunlight enters the earth's atmosphere, blue light is scattered away and at the end of its journey in the sky, only red and orange wavelengths remain in the beam.

hence at sunrise and sunset, the sky appears reddish orange.