Chp 16 Reading Assignment 1: What is Light?

Rank the following types of electromagnetic waves, from lowest frequency (top) to highest frequency (bottom), using the figure.

1. AM radio wave 2. microwaves 3. visible light 4. x-rays

Which of the following wavelengths fall in the range of visible light?

7.1 x 10--7m 5.4 x 10--7m 3.9 x 10--7m

Match the type of magnetic field on the left with the electric field it generates on the right.

A changing magnetic field generates=an electric field. A constant magnetic field generates =no other field.

Assuming that an object is illuminated with white light, match the colors of light absorbed in the left column with the color the object would appear to be in the right column.

An object that absorbs green light will appear to be= a combination of blue and red, or magenta. An object that absorbs green and blue light will appear to be= red. An object that absorbs red and blue light will appear to be= green.

If our eyes perceive an object to be the color red, which of the following colors are being absorbed by pigments in the object?

Blue Green

Which of the following travel at the same speed?

Electromagnetic waves Light

Match the type of electromagnetic wave on the left to the relative wavelength on the right.

FM radio waves=long infrared waves=medium gamma rays=short

Match the type of electromagnetic wave on the left to the relative frequency on the right.

FM radio waves=low infrared waves=medium gamma rays=high

If our eyes perceive an object to be the color blue, which of the following colors are being absorbed by pigments in the object?

Green Red

Match the relative size of the frequency with the relative size of the wavelength for an electromagnetic wave.

Low frequency= Large wavelength Medium frequency= Medium wavelength High frequency= Short wavelength

Match the type of electromagnetic wave with a process which normally produces it.

Radio waves are produced by= electric circuits. Infrared waves are produced by= warm bodies. Ultraviolet waves are produced by= excited atoms.

A set of one red and one blue light bulb illuminates an otherwise dark room. You pick up a book you know to have a red cover in white light and it still appears to be red. Which of the following statements are true?

The book cover gets warmer. The blue light is absorbed. The red light is reflected.

Which are the two colors at the ends of the visible spectrum?

Violet Red

Separating colors out of a beam of white light can be undone by

a second prism.

An electromagnetic wave is made of up of

changing magnetic fields. changing electric fields.

It is the motion of a that produces a magnetic field.

charge

Electric and magnetic fields are both produced by moving . (Enter only one word per blank.)

charges

A changing magnetic field will generate an field.

electric

A changing electric field produces a changing magnetic field. As the changing electric field moves and produces a magnetic field, the changing magnetic field produces a changing electric field. We call this chain of events an wave.

electromagnetic

An accelerating charged particle generates a changing electric and magnetic field. These fields move away from the charge. We call these traveling fields a(n) wave.

electromagnetic or light

White light is composed of

electromagnetic waves of different wavelengths. a combination of all the colors.

Radio waves and light are both examples of electromagnetic waves. They differ only in their . (fill in the blank with one word)

frequencies, frequency, wavelength, or wavelengths

Maxwell predicted the speed at which an electromagnetic wave should travel. He realized it was the same as the speed of in a vacuum.

light

When two (or more) different colors come into the eye at the same time, they mix and we only see the result of the mixing. When both red and blue light are reflected off an object, we perceive the object to be the color

magenta, purple, or fuchsia

Moving charges cause

magnetic fields. electric fields.

For objects that do not create their own light (the way light bulbs do), the color we perceive the object to be is due to the light that is off them. The color we perceive when looking at the object can change if the light source has a different wavelength.

reflected, scattered, bounced, bouncing, reflecting, scattering, bounce, reflect, or scatter

The difference between radio waves and light waves is

their frequencies. their wavelengths.

A charge will produce a magnetic field if the charge is

traveling with a constant velocity. accelerating.

One major difference between an electromagnetic wave and other types of waves is that electromagnetic waves have a fixed speed, c. This means the wavelength times the frequency of electromagnetic waves always gives the same number, c. Thus, when the frequency becomes high, the becomes short.

wavelength

Newton separated white light into a spectrum of colors by passing a ray of white light through a prism. Newton then took that spectrum and passed it through a prism again which resulted in light coming out the other end.

white

A changing magnetic field

will generate an electric field. implies there are accelerating charges.

When two (or more) different colors come into the eye at the same time, they mix and we only see the result of the mixing. When both red and green light are reflected off an object, we perceive the object to be the color.

yellow

Passing white light through a prism allows one to see

yellow light. red light. blue light.