Physics 2 Ch. 26 Online HW

What is the frequency of an electromagnetic wave that has a wavelength of 300,000 km?

1 Hz

If the Sun were to disappear at this moment, we wouldn't know about it for how long?

8 minutes

While Earth is experiencing a total sphere eclipse, an observer on the side of the Moon facing Earth would see:

A dark area moving across the face of Earth

When an astronaut on the Moon experiences a solar eclipse, observers on Earth see:

A lunar eclipse

Which best shields you from sunburn when at the beach? (A sheet of glass between you and the sun, a cloudy day, frequent turning of your body)

A sheet of glass between you and the sun

The main difference between the retina of a human eye and that of a dog's eye is the:

Absence of cones in a dog's retina

Materials generally become warmer when light is:

Absorbed by them

The source of all electromagnetic waves is:

Accelerating electric charges

Which of these travel with the greatest speed in a vacuum? (Game Rays, x-rays, radio waves, light waves)

All of them have the same speed

A total shadow is called:

An umbra, and a partial shadow a penumbra

Glass is transparent to wave frequencies that:

Are below its natural frequencies

When visible light is incident upon clear glass, atoms in the glass:

Are forced into vibration

Information-carrying nerves are connected to the retina at the:

Blind spot

If a light signal and a radio signal were emitted simultaneously from Alpha Centauri, the first to reach Earth would be:

Both of them at the same time

The sensation of color is seen when light falls on the eye's:

Cones

An annular eclipse of the Sun occurs when the Moon doesn't quite cover the Sun in the zone of totality. This means that the Moon is:

Farther than usual from the Earth

A main difference between a radio wave and a light wave is:

Frequency and wavelength

If an electron vibrates up and down 1000 times each second, it generates an electromagnetic wave having a:

Frequency of 1000 Hz

Infrared waves are often called heat waves because they:

Induce resonance in molecules and increase internal energy in a substance

Earth's atmosphere is opaque to waves that are concentrated in the:

Infrared part of the spectrum

Most of the waves in an electromagnetic spectrum are:

Invisible

Colors are barely seen or not at all in nighttime because moonlight:

Is too dim to activate the retina's cones

Compared to average speed in air, the average speed of a beam of light in glass is:

Less

If an electric charge is shaken up and down frequently enough:

Light can be emitted

Compared to ultraviolet waves, the wavelength of infrared waves is:

Longer

If the color spectrum ranges from red to violet, then it ranges from:

Low frequencies to high frequencies and low wavelengths to high wavelengths

Compared to ultraviolet waves, the frequency of infrared waves is:

Lower

The moon would be at its fullest just before the time of a:

Lunar eclipse

A changing electric field includes a changing:

Magnetic field

A main difference between a radio wave and a sound wave is:

Medium or no medium

A lunar eclipse occurs when the:

Moon passes into Earth's shadow

What is the wavelength of an electromagnetic wave that has a frequency of 3 kilohertz?

More than 1 km

What is the wavelength of a 1-hertz electromagnetic wave?

More than 1 m

The cones in the retina of the eye are:

Most densely packed at the center of vision

Electromagnetic waves consist of:

Oscillating electric and magnetic fields

The fact that you can see stars in the nighttime sky is evidence that:

Our atmosphere is transparent to visible light and light can travel in a vacuum

A partial solar eclipse occurs for people in the Sun's:

Penumbra

Which of these electromagnetic waves has the longest wavelength? (Radio waves, infrared waves, light waves, x-Rays, ultraviolet waves)

Radio waves

Which color of light gets through red glass? (Red,cyan)

Red

When ultraviolet light is incident upon glass, atoms in the glass:

Resonate

In the periphery of our vision, we are:

Sensitive to movement, but cannot see color

A new Moon appears in the sky just before the time of a:

Solar eclipse

Which of the following can't travel in a vacuum? (Light wave, radio wave, sound wave)

Sound wave

Which of these fundamentally differ from the others? (Radio waves, x-rays, gamma rays, sound waves, light waves)

Sound waves

A pair of sunglasses and a pair of clear reading glasses are left in the sunlight. The hotter glasses will be the:

Sunglasses

A solar eclipse occurs when:

The Moon's shadow is cast on Earth

The round spots of light on the ground beneath a tree on a sunny day are images of:

The Sun

The size of the pupil in your eye depends on:

The brightness of light in the room and your mood

Compared to radio waves, the velocity of visible light waves in a vacuum is:

The same

Consider light energy that is momentarily absorbed in glass and then re-emitted. Compared to the absorbed light, the frequency of the re-emitted light is:

The same

The speed of light in the void between molecules in glass is:

The same as its speed in a vacuum

Metals are shiny because:

Their electrons vibrate to the oscillations of any incident light

Red-hot and blue-hot stars appear whit to the eye because:

They are too dim to fire the cones

Sunburns are produced by:

Ultraviolet light

The natural frequency of the atoms in glass is in the:

Ultraviolet part of the spectrum

A total solar eclipse occurs for people in the Sun's:

Umbra

Glass is transparent to:

Visible light

Which of these electromagnetic waves have the shortest wavelength? (Ultraviolet waves, light waves, infrared waves, radio waves, x-Rays)

X-rays

In 1887, Albert A. Michelson sent a beam of light from a revolving mirror to a stationary mirror 15 km away. Find the time interval between light leaving and returning to the revolving mirror and find a time for a pulse of laser light to reach the Moon and to bounce back to Earth:

t = 1.0 x 10^-4 s t = 2.6 s

The nearest star beyond the Sun is Alpha Centauri, 4.2 x 10^16 m away. If we were to receive a radio message from this star today, find the time when it would have been sent. Find the frequency of this radiation. Find the time required for a pulse of radar waves to each an airplane 4.8 km away and return:

t = 4.4 years ago f = 10 GHz t = 3.2 x 10^-5 s