Science of Color and Light

frequency

# of vibrations per second

What is the range of wavelengths in the visible spectrum expressed in nanometers and in meter?

400-700nm 1 billion nm=1 meter

an automobile horn has a frequency of 440 Hz. What frequency is

473.19hz

MAgenta+Cyan

BLue

What is color?

Color is

R+B

Magenta

constructive interference

waves are in phase

Destructive interference

waves are out of phase

GReen+ Blue

Cyan

Determine the frequencies of Red lite (lamdba=650nm) and blue light (lambda= 460nm)

F= Red 4.62*10^14Hz, Blue

Rayleigh Scattering

If the size scattering particle is much less than the size of the wavelength of the light, we find that the probability of scattering the light is proportional to the reciprocal of the wavelength to the power of 4.

Under what conditions would the shadow of a ball have no umbra?

If theres only one source of light

what is a wave?

A wave is a propagating disturbance

Can the image formed by a convex mirror be either larger or smaller than the object?

The image formed by a convex mirror can be only the same size or smaller than the object. This is due to the mirror equation and the lateral magnification equation

Dispersion

When light breaks into different colors (Newton Said this). Each color bends off when refracted by glass. Visible lite split or dispensed when it passes thru a lense or prism. shorter wavelengths (purple+blue) bend the most. longer wavelengths like red and orange lite bend the least.

Solar Eclipse

When sun is blocked moon is in between the Sun+Earth (Penumbra still sees part of the Sun)

whats mean when a medium is described as "Dispersive?"

When waves from different frequencies travel at different speeds. An example of this would be when oil collides with water.

How many images of a penny will be produced by a 2-mirror kaleidoscope if the angle between the mirrors is 90, 60, 45 or 30 degrees.

A 90 degree mirror will produce 4 images, a 60 degree mirror will produce 6 images, a 45 degree mirror will produce 8 images and a 30 degree mirror will produce 10 images.

3 projectors are adjusted to produce white light on a screen. If you stand in front of the red projector, what color will your shadow be?If you stand in front of the green projector what color will your shadow be? If you stand in front of the blue projector, what color will your shadow be?

REd projector= Cyan. Green projector= magenta. Blue projector= yellow

YEllow+Magenta

Red

If the frequency decreases (wavelength increases)

Red Shift

Yellow+Blue

WHite

Describe an expirement that demonstrates the particle nature of light

photoelectric effect

lightning strikes the ground one km away (a) How long does it take the light to reach us? (b) How long does it take the sound (thunder) to reach us?

t= 3x10^-6s b. 2.93s

How do cops use doppler effect to determine the speed of a car?

the radars that cops use bounce microwave radiation off off vehicles and find the reflected waves provides a measure of the vehicle speed.

Why is the sky blue and the setting sun red?

the sky is blue and the sun sets red because of Rayleigh scattering. If the size of the scattering particle is smaller than the size of the lights wavelength than the probablility of scattering light is proportioned ti the reciprocal of the wavelength to the fourth power. the color blue will be scattering more than red.

Interference

the sum of waves traveling in the same medium

Transversal

transverse wave is where the vibration is perpendicular to the direction of motion example: light, water waves

Magenta+Cyan+yellow

Black

What are the frequencies of the wavelengths?

Blue: 455 ~ 485 nm Green: 500 ~ 550 nm Yellow: 570 ~ 590 nm Red: ~ 625 nm

Explain why the colors are "reversed" in a secondary rainbow.

Colors are reversed in secondary rainbow because of double internal reflection

Lunar Eclipse

Earth is between the Sun and Moon

DEtermine the wavelength of radio waves transmitted by an FM radio station having a frequency of 89.5MHz (1MHz=10^6 Hz)

Lambda=3.35m

Which determines speed of a wave?

Medium through which it travels

The law of reflection

The angle of incidence equals the angle of reflection

Can the image formed by a concave mirror be either larger or smaller than the object?

The image formed by a concave mirror can be either larger or smaller than the object depending on location of the object

A spotlight produces a shadow of a ball on a wall. What happens to the size of the umbra as the ball is moved farther away from the light?

The size of the umbra gets smaller the farther the ball is moved

Why wouldn't you like to use specular reflector as a movie screen?

Using a specular reflector as a movie screen would not work because some viewers watching the movie would not see any light, yet other people in the audience would be blinded by the light.

DEtermine the speed of light in vegetable oil and diamond if their indices of refraction are 1.51 and 2.42 respectively

V=1.99x10^8 m/s (vegetable) V=1.24x10^8 m/s (diamond)

Yellow+BLue=

WHite

Why is water greenish blue (cyan)

While the sky is blue because blue is strongly scattered by molecules in the atmosphere, water is bluish green because red is absorbed by molecules in the water, hence leaving the water to have a cyan. So water is cyan because it absorbs red light and reflects green and blue. The foam in the waves is white because, like clouds, it is composed of a variety of tiny water droplets that scatter all the visible frequencies.

Cyan+REd

White

Green+Magenta

White

Red+ Green+ Blue

White

Red+Green

Yellow

Why wouldn't you want to use a diffuse reflector when shaving or applying make up?

You would not want to use a diffuse reflector when shaving or applying makeup because when light falls on a rough surface the light is reflected in every direction and you cannot see your own reflection.

How could you determine whether a certain green light has a single wavelength or a broad distribution of wavelengths?

a certain green light wavelength is only the color while a broad distribution of wavelengths would have more than just the color green in the spectrum.

photosynthesis

a process by which green plants use energy from the the sun to transform water carbon dioxide, and minerals into oxygen and organic compounds. Via the energy converting the chemical chlorophyll.

longitudinal

a wave in which the vibration is along the direction of motion

Why are clouds white on a sunny day?

because blue, green, and red are combined to make white. This is due to the fact water droplets scatter and produce different frequencies. The smallest scatter creates blue slightly larger scatter creates green and even larger water droplets scatter and create red. When all three 0f the colors are combined they white.

photos on the moon show a colorless sky. Explain Why?

because the moon has no atmosphere

If the frequency increases (wavelength decreases)

blue shift

Doppler Effect

change in frequency as a result of motions. If the frequency increases.

How is an electromagnetic wave generated?

if a charger is rod moved back and fourth oscillating elcectric and magnetic fields are generated.