light and mirrors review. true or false? black and white are colors of light. false, black is not a...

Light and Mirrors Review

True or False?

• Black and white are colors of light.

• False, Black is not a color of light. It is a lack of light.

• However, black and white could both be a color of pigment.

• What color is produced when red and blue light are combined?

• Magenta

• What color is produced when yellow and cyan pigments are combined?

• Green

Color lists

• Primary colors of light R, G, & B• Primary colors of pigment M, Y, & C• Secondary colors of light M, Y, &

C• Secondary colors of pigment R, G, &

B• Complimentary colorsR & C, G & M, B & Y

A magnifying make-up mirror is held 4.0 cm from your face resulting in a magnification of 3.0 times. Determine the distance between the image of your face and the focal length of the mirror.

di = -12 cm

f = 6 cmDistance from f to di = 18 cm

What is the speed of light?

• 3.0 x 108 m/sec. Think again….

• This is the speed of light in a vacuum.

• Other medium could slow light down a little, a whole lot or even stop it all together.

• Light is not just restricted to visible light.

Electromagnetic Spectrum

• PRIVUX G.C. • Power, Radio, Infrared, Visible, Ultraviolet,

X-ray, Gamma, Cosmic

• Visible light = Roy G. Biv • Note: the capital letters are the primary colors

More E.M. spectrum• Cram the two spectrums together, make some

small changes and you have the order:• Radio, • Microwave, • Infrared, • red, orange, yellow, green, blue, indigo, violet,• Ultraviolet, • X-ray, • Gamma

E.M spectrum summary

• The wavelength of Radio waves are very long while the wavelength of X-rays are short.

• This means that the frequency of Radio waves is very low while X-rays have a high frequency.

• Waving frequently requires more energy.• X-rays have much more energy than Radio• What color has the greatest frequency?

» violet

• Two lights have equal luminance on a surface. One bulb has a luminous flux of 1750 lumens and is 1.5 meters away. The other has a luminous flux of 1000 lumens. How close is the second blub to the surface?

• P1= 1750 lm

• r1= 1.5 m r2= 1.134 m

• P2= 1000 lm

Which cup is opaque?

Blue = Opaque, Green = Translucent, Clear = Transparent

Is all light visible with the human eye?

• Only a very small fraction of light can be seen by the human eye. Most “light” in the electromagnetic spectrum can is composed by waves either too large or too small for the eye to detect.

See other good calculation questions in appendix B!