Chapter 26 & 27 color and light

What causes light to be emitted?

Accelerated motion of electrons.

What are the two components of an electromagnetic wave?

Vibrating electric and magnetic fields.

How does the frequency of a wave relate to its energy?

Higher frequency means higher energy.

What part of the electromagnetic spectrum is visible to the human eye?

The visible light spectrum (red to violet).

Which type of electromagnetic wave has the highest energy?

Gamma rays.

Why does ultraviolet light cause sunburns?

It has higher energy than visible light and can penetrate the skin.

How does light travel through transparent materials?

It is absorbed and reemitted by electrons in the material, slowing down the speed of light.

Why does glass not transmit ultraviolet or infrared light?

Glass absorbs these frequencies instead of reemitting them.

What determines if an object appears opaque?

If it absorbs light without reemitting it as visible light.

What is the difference between an umbra and a penumbra?

An umbra is a total shadow, while a penumbra is a partial shadow.

Why do solar eclipses occur?

The Moon blocks sunlight from reaching the Earth, creating a shadow.

What part of the eye is responsible for most of the light bending?

The cornea.

What is the function of rods and cones in the retina?

Rods detect low light, while cones detect color.

What is lateral inhibition in vision?

The process where bright areas prevent neighboring areas from appearing as bright, increasing contrast.

What determines the color an object appears?

The frequencies of light it reflects or transmits.

What happens when an object absorbs all visible light?

It appears black.

What are the additive primary colors of light?

Red, green, and blue (RGB).

What happens when red, green, and blue light are combined?

White light is produced.

What are the subtractive primary colors of pigments?

Cyan, magenta, and yellow (CMY).

What color will a blue object appear in yellow light?

Black, because yellow does not contain blue wavelengths to reflect.

Why does the sky appear blue?

Shorter wavelengths (blue) are scattered more by small atmospheric particles.

Why does the sky appear whiter on a humid day?

Larger particles scatter all wavelengths, creating a whitish appearance.

Why do sunsets appear red?

As light travels through more atmosphere, shorter wavelengths scatter away, leaving longer wavelengths like red and orange.

What would happen if the sky scattered orange light instead of blue?

Sunsets would appear blue.

Why do clouds appear white?

Water droplets scatter all wavelengths of visible light.

What causes clouds to appear gray or dark?

Thicker clouds absorb and scatter more light, reducing the amount that reaches your eyes.

Why does water appear blue-green?

Water absorbs red light more than blue, leaving mostly blue and green light.

How does glacier runoff make lakes appear vivid blue?

Tiny suspended particles scatter light, enhancing the blue color.

What is the speed of light in a vacuum?

300,000,000 m/s (or 3.0 × 10⁸ m/s).

How does refraction affect the speed of light in different materials?

Light slows down in denser materials like water and glass.

What happens when light passes from air into water at an angle?

It bends toward the normal due to refraction.

What is the difference between reflection and refraction?

Reflection bounces light off a surface, while refraction bends light as it changes medium.