CH 11-2 Reflection and Refraction of Light

8/9/2019 CH 11-2 Reflection and Refraction of Light

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11-2 Reflection and

refraction of Light


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Reviewing 11-1 Soundy Sound frequencies above 20,000 Hz are called

__________ waves.A. infrasonicB. infraredC. subsonicD. ultrasonic

y Describe the Doppler effect. You may draw a picturebut be sure to use vocabulary words to explainit(intensity, frequency, pitch, amplitude, energy)

y In which of the following environments would sound

waves not travel?A. at altitudes of 10,000 15,000 m

B. in solid aluminum

C. on the Moon

D. under water


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Absorption, Transmission, andReflection

y The opaque material in this

candleholder only absorbs and

reflects lightno light passes

through it.

y Materials that allow some light to

pass through them, like the

material of this candle holder are

translucent.

y Transparent materials, such as

this candleholder transmit almost

all the light striking them, so you

can see objects clearly through

them.


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Regular and Diffuse Reflectiony A smooth, even surface such as a pane of glass

produces a sharp image by reflecting parallel lightwaves in only one direction.

y

Reflection of light waves from a smooth surface isregular reflection.

y To cause a regular reflection, the roughness of a

surface must be less than the wavelengths it reflects.

y

Reflection of light from a rough surface is diffusereflection.

y Diffuse reflection is a type of scattering that occurs

when light waves traveling in one direction are made

to travel in many different directions.


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Reviewing Refractiony Refraction is caused by a change in the

speed of a wave when it passes fromone material to another.

y Index of refraction is the ratio of the

speed of light in a vacuum to the speedof light in the material.

y The index of refraction indicates howmuch the speed of light is reduced in the

material compared to its speed in emptyspace.

y The larger the index of refraction, themore light is slowed down in thematerial.


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Refraction of Light

y White light, such as sunlight, is

made up of light waves with

range of wavelengths.

y Prism refracts the light twiceonce when it enters the prism

and again when it leaves the

prism.

y

The longer wavelengths of lightare slowed less and are bent the

least.

o This causes the different colors of

light separate and emerge out of

the prism


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Mirages Mirages result when the air at ground level is much

warmer or cooler than the air above.

The density of air increases as air cools and lightwaves move slower in cooler air than in warmer air.

Light waves are refracted as they pass through airlayers with different temperatures.


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Reviewing 11-1 Sound

y Sound frequencies above 20,000 Hz are called

__________ waves.

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CH 11-2 Reflection and Refraction of Light