Refraction and Dispersion

Question 1

What happens to light entering the dielectirc medium?

Answer 1

~ light slows down as it propogates through

~ plane wave normal bends toward th surface perpendicular

Question 2

What is Snell’s law?

Answer 2

~ n = Vair/Vglass = sinΦair/sinΦglass

~ the index of refraction is the ratio of VELOCITIES in air and the glass

Question 3

What is the relationship between index of refraction and wavelength?

Answer 3

~ index of ref decreases with LONGER wavelengths

Question 4

What is crown glass?

Answer 4

~ soda lime

Question 5

What is flint glass?

Answer 5

~ PbO-K2O-SiO2

Question 6

What is the emperical dispersion equation/the cauchy equation?

Answer 6

~ n = A + B/2 + C/(λ^4)

Question 7

What is a prism?

Answer 7

~ the second surface is NON-COPLANAR with the first so that different colors fan out in the exiting beam

Question 8

What is an indicator of dispersion?

Answer 8

~ angle of spread

Question 9

What causes chromatic abberation in lenses?

Answer 9

~ different components of white light focus at different positions

Question 10

How do you cure chromatic abberation in lenses?

Answer 10

~ use an achromatic doublet –> strong converging lens

~ made of crown glass and a weak diverging lens make out of flint glass