Ch 16

Question 1

Reflection

Answer 1

change in direction of a wavefront at an interface between two different media so that the wavefront returns into the medium from which it originated

Question 2

Law of reflection

Answer 2

1) the incident ray, the reflected ray and the normal to the reflection surface at the point of the incidence lie in the same plane
2) the angle which the incident ray makes with the normal is equal to the angle which the reflected ray makes to the same normal
3) the reflected ray and the incident ray are on the opposite sides of the normal

Question 3

Refraction

Answer 3

change in direction of a wave due to a change in its transmission medium

Question 4

Mirages

Answer 4

naturally occuring optical phenomenon in which light rays are bent to produce a displaced image of distant objects or the sky
–cold air is denser than warm air, therefore, has a greater refractive index;; as light ravels at a shallow angle along a boundary between air of different pthe light rays bend towards the colder air

Question 5

Rainbows

Answer 5

optical and meteorological phenomenon that is caused by both reflection and refraction of light in water droplets resulting in a spectrum of light appearing in the sky;; it takes the from of a multicoloured arc;; caused by sunlight always appear in the section of sky directly opposite the sun

Question 6

Primary Rainbow

Answer 6

water is more dense than air, light is refracted as it enters the drop: red is bent less, blue more;; the light is then refracted again as it leaves the drop, the colors of white light have been dispersed
BLUE light: will leave the drop at an angle of 40 degrees from the beam of light
RED light: will leave at 42 degrees from the beam of light
cannot see both colors from one drop

Question 7

Secondary Rainbow

Answer 7

generated when sunlight makes two internal reflections in the drops instead of one;; weaker than primary;; colors reversed

Question 8

Halo

Answer 8

ring of light enciriling and extending outward from the sun or moon;; created as sunlight is refracted as it passes through ice crystals;; indicates cirriform clouds (high, thin clouds composed of ice crystals

Question 9

Two types of Halo’s

Answer 9

22 degree– refraction of light through randomly falling ice crystals
46 degree– refraction of light through hexagonal column-type ice crystals

Question 10

Sun Dogs

Answer 10

scientific name parhelia are an atompshereic phenomenon that consists of a pair of brights spots on either side of the sun;; often co-occuring with a luminous ring known as a 2 degree halo
–created as white light is refracted through ice crystals in the form of hexagonal plates;; similar to the dispersion of white light as it passes through a prism

Question 11

Green Flash

Answer 11

sometimes occur right before sunset or right before sunrise;; visible above the upper rim of the disk of the sun;; usually lasts for no more than a seconds or two;;can resemble a green ray shooting up from the sunset point;; occur because the atmosphere can cause the light from the sun to separate out into different colors;; stem from slightly different causes, and therefore some types of them are more common

Question 12

Diffraction

Answer 12

occurs when light is bent as it passes around an obstacle or a slit that has approximately the same size as the wavelengths of the light itself;; “bent” waves will interact with each other producing an interference pattern

Question 13

Constructive interference

Answer 13

when a ridge( trough) from one wave is superimposed on a ride (trough) from another- end up with a large amplitude

Question 14

Destructive interference

Answer 14

with the ridge of one wave is superimposed on the trough of another–they cancel out producing no amplitude

Question 15

Corona

Answer 15

produced by the diffraction of light from either the sun or the moon by individual small water droplets and sometimes tiny ice crystals of a cloud or on a foggy glass surface;; consists of small number of concentric colored rings around the celestial object and central bright aureole;; differ from haloes in that the latter are formed by refraction (rather than diffraction) from comparatively large rather than small ice crystals

Question 16

Cloud Iridescence

Answer 16

when the drops in a cloud have many different sizes, the corona can become distorted;;

Question 17

iridescence

Answer 17

areas within 20 degrees of the sun where the corona has become distorted producing patches of color

Question 18

Glory

Answer 18

often view form an airplane;; when a cloud has drops with sizes 50 micrometers, a colored rings will appear to circle the shadow of an airplane on a cloud;; this diffraction phenomena is called glory