Physics 27 Questions

Blue. The lowest frequency light we can detect appears to most people as the color red, and the highest frequency as violet.

They are forced into vibration, absorbing or emitting electromagnetic waves. Once vibrating, they send out their own em waves, just as tuning forks send out sound waves.

it is absorbed. At resonant frequencies at which amplitudes of oscillation are large, light is absorbed.

it is reemitted.

red

A pigment selectively absorbs some frequencies of light and transmits others.

A colored piece of glass warms quickest because it absorbs more frequencies of light, thus converting the energy to temperature.

The leaves absorb the energy of the red light, rather than reflect it, and so become warmer. They are not red, so they do not reflect it!

The petals absorb rather than reflect the green light. Because green is the only color illuminating the rose and green contains no red to be reflected, the rose reflects no color and appears black.

The front surface reflection is white because the light doesn't go far enough into the colored glass to allow the absorption of nonred light. Only red light reaches the back surface because the pigments in the glass absorb all other colors; the back reflection is red.

all of these: If you shine white light through a glass filter passing any spectral color, then that color will come through the filter. White light can be separated into all colors of the spectrum using a prism, and then these colors can be recombined to make white light. In a rainbow, sunlight is spread into all the colors by passing through water drops.

yellow-green. Check out the radiation curve of sunlight

yellow-green

A graphical distribution of brightness versus frequency, of sunlight. Most whites produced from reflected sunlight share this frequency distribution

Red: low, green: middle; blue: high frequencies

Adding appropriate amounts of red plus green plus blue lights can produce almost any color of the spectrum.

absence of light

Cyan + red = white cyan is made of blue + green, and (blue + green + red) = white. When each color is added to its opposite, white occurs.

They can be added together to make white light.

cyan, the complementary (opposite) color

Magenta, cyan, and yellow

Magenta, cyan, and yellow

primary colors are CMY

small bells

small particles

Air molecules have resonances in the ultraviolet, so they scatter blue light more than red light. These particles emit light most strongly in the UV region, so they have natural frequencies higher than that of visible light. This means that blue light will be closer in frequency that red light, scattered more strongly

Large particles in the atmosphere scatter longer wavelength light that adds to the blue light to create white light.

If we look at distant dark mountains, very little light from them reaches us, and the blueness of the atmosphere between dominates. The blueness we think is the mountains is actually the low-altitude "sky" between the mountains and us!

The longer path length of sunlight at sunrise and sunset scatters out more blue light. At noon, sunlight travels through the least amount of atmosphere to reach Earth. Only a small amount of high-frequency light is scattered, to make the Sun look yellow.

Different particles in the air each day scatter and absorb different wavelengths of light, thus giving the sky many different colors.

If low-freq light were scattered, noon skies would appear red-orange. At sunset, more reds would be scattered by longer path of sunlight, and sunlight would be predominantly blue and violet. Sunsets would appear blue!

The blue in the white light reflected is scattered on the way to us. By then, it is weak in high frequency, strong in low frequency. Hence, yellow. Further snow-covered mountains have an orange tinge, same as sunsets appear orange.

Water droplets of different sizes scatter a variety of light frequencies, resulting in a white cloud. The froth in waves is white because it also is composed of a variety of tiny water droplets, scattering light of all visible frequencies.

The cloud becomes dark

infrared

red. Thus the complementary color of red, cyan, is visible

cyan

Water absorbs red light. White minus red is cyan.

Disagree. Red is a primary color, it cannot be produced by mixing.

Stars do glow during the day, but we can't see them because of the glare of sunlight. When the sun is up, the blue color in sunlight gets scattered all over the atmosphere, turning the sky the familiar bright blue color. Intensity of the sun's light is far greater than that of the stars, as their intensity decreases by distance

Since Yellow light = red + green, use Blue light to change to black (red + green + blue = black)

secondary colors, by color subtraction

black

white light yellow is red + green red + green + blue = white

magenta light green light + (red + blue) = white

white light

sky and lakes