PHYSICS CHAPTER 14 NOTES

for each of the following cases, will light rays be bent toward or away from the normal? 1: ni > nr, where thetai = 20 degrees 2: ni < nr, where thetai = 20 degrees

1: away 2: toward

in which of the following situations will light from a laser be refracted? 1: traveling from air into a diamond at an angle of 30 degrees to the normal 2: traveling from water into ice along the normal 3: upon striking a metal surface 4: traveling from air into a glass of iced tea at an angle of 25 degrees to the normal

1: yes 2: no angle 3: all reflected 4: yes

every lens has __ focal points; one on each side

2

STUDY ALL SAMPLE PROBLEMS IN THE NOTES

:)

If light waves strike a boundary between two mediums __ (perpendicular to the boundary), the light waves continue in a straight line; no refraction occurs

at a right angle

If light waves strike a boundary between two mediums __ with the normal (Ѳi), the light waves change direction; refraction occurs

at an angle

__ refraction: The sun can be seen after it has passed below the horizon due to refraction of the sun rays as they enter the earth's atmosphere

atmospheric

When light moves from a material in which its speed is slower to a material in which its speed is faster, the ray is bent __ the normal

away from

When the light exits the glass, the rays are bent __ the normal at the same angle

away from

HYPEROPIA: image position is __ the retina. person is said to be farsighted. hyperopia is corrected with a __ lens

behind converging

The index of refraction (n) from the two materials at a boundary can be used to determine how much a ray of light will __ as it passes through the boundary

bend/refract

in total internal reflection, the ray is reflected at the __ as though it struck a reflective surface

boundary

Greater magnification can be produced __ microscope - two converging lenses __ telescope - two converging lenses

compound refracting

When rays that are parallel to the principle axis pass through a lens, the rays are bent, and a point image forms at the focal point of the lens: In a __ lens, it is the point where the rays meet In a __ lens, the rays will never meet thus it is the point from which the rays appear to originate

converging diverging

CONTACT LENS: worn over the __ of the eye. floats on a thin layer of tears

cornea

the minimum angle of incidence for which total internal reflection occurs. angle of refraction is 90. refracted ray moves parallel to the boundary

critical angle

When the boundary is __, the normal line changes for each point along the boundary

curved

a transparent object that refracts light rays, causing them to converge or diverge to create an image

curved boundary

Rainbows are created by __ of light as the rays pass through water droplets

dispersion

the process of separating polychromatic light into its component wavelengths

dispersion

MYOPIA: image position is __ the retina. person is said to be nearsighted. myopia is corrected with a __ lens

diverging

__ lens: image is always virtual and upright, always reduced in size, and always found inside the focal point

diverging

the distance from the focal point to the center of the lens

focal length

When rays that are parallel to the principle axis pass through a lens, the rays are bent, and a point image forms at the __ of the lens

focal point

the angle between the refracted ray and the normal

incoming theta

index of refraction decreases with __ wavelength

increasing

As the object moves towards the lens and approaches the focal point, the image becomes __ and __

larger farther away

the ratio of the speed of light in a vacuum to its speed in a given transparent medium. always greater than one because light always travels slower in a substance than a vacuum

law of refraction

the focusing of different colors of light at different distances behind a lens. can be greatly reduced by combining a converging and a diverging lenses made of different types of glass

lens abberation

Ratio of image height to object height

magnification

The speed of light depends on the __ (Speed of light in air > in glass > in water)

medium

critical angle calculation: can only be used when __ is greater than __

ni > nr

When the object reaches the focal point, the exiting rays are parallel and __ is formed

no image

The image formed by the first lens is treated as the __ for the second lens

object

Because the angle of refraction is the same, the exiting and entering rays are __; the exiting ray is just __

parallel displaced

For an object infinitely far away (incoming rays are parallel), a __ is formed

point image

Assumed that the lens is very thin (lens thickness must be much smaller than its focal length) -Equation is identical to the mirror equation -Applies to both converging and diverging lenses -focal length is __ for a converging lens -focal length is __ for a diverging lens

positive negative

Overall magnification is the __ of the magnifications of the separate lenses

product

images can be...

real or virtual upright or inverted

Objects appear to be in different positions due to __

refraction

the bending of a wave disturbance as it passes at an angle from one medium to another

refraction

Mirages are the result of __ -heat from the ground heats the air above it leading to a change in __ and a different refractive index -the observer concludes that a pool of water must be causing a "reflection"

refraction density

It helps to understand __ if you think of light rays as a car transferring from a paved road (fast speed) to a muddy road (slow speed). If the car is at an angle, the difference in speed between the two roads will cause the car's __ to change

refraction direction

Lenses form images through __, whereas mirrors formed images through __

refraction reflection

EYESIGHT: Cornea, in conjunction with the lens, __ light that enters the eye. Light is directed towards the light sensitive __ in the back of the eye

refracts retina

internal reflection application

slide 37 in notes

The larger the index of refraction is, the __ light travels in that substance

slower

__ aberration occurs for lenses too

spherical

__ can occur when light moves from a medium with a higher index of refraction to one with a lower index of refraction

total internal reflection

the complete reflection of light at the boundary of two transparent media; this effect occurs when the angle of incidence exceeds the critical angle

total internal relfection

When light moves from a material in which its speed is faster to a material in which its speed is slower, the ray is bent __ the normal

toward

When light traveling in air enters glass, the light rays are bent __ the normal at a certain angle

towards

Refraction is caused by the change in __ associated with a change in __

velocity medium

When the object moves inside the focal point, the exiting rays diverge and a __ is formed (the image appears on the same side as the object)

virtual image

Index of refraction depends on the __ of light

wavelength

-The angle that light bends when entering a different medium depends on the __ of the light -This explains why a __ is produced -Each color of light has a different __ -Each color is __ by a different amount

wavelength spectrum wavelength refracted

Lenses are named based on...

what happens to the light rays as they pass through the lens