Astronomy CH 4

Select all the instruments that can be used to spread light out into its component colors (a spectrum).

- prism - grating

Match each type of spectrum with its correct description.

1. Continuous - All colors are present; formed by dense materials All colors are present; formed by dense materials 2. Emission-line -- Only specific colors are present; formed by hot, thin gases Absorption-line 3. Absorption-line -- Almost all colors are present, but specific colors are dim or missing; formed by cooler gases

Match each type of spectrum with the kind of object that emits it.

1. Continuous -- Filament of an incandescent lightbulb Filament of an incandescent lightbulb 2. Emission-line -- Hot, tenuous interstellar gas cloud Hot, tenuous interstellar gas cloud 3. Absorption-line -- Cooler gas cloud in front of a much hotter object Cooler gas cloud in front of a much hotter object

Select all the types of astronomical objects from which astronomers have detected radio waves.

1. Forming stars 2. Supernovas (exploding stars) 3. Interstellar gas clouds 4. Active galaxies

Match the units to the properties of light that they measure.

1. J - Energy 2. Hz - Frequency 3. nm - Wavelength 4. Meters per second - Speed

Select all that are properties of light.

1. Light is made of electric and magnetic energy. 2. The speed of light in empty space is constant. 3. Light can travel through a vacuum.

Arrange the types of electromagnetic waves in order from longest (top) to shortest (bottom) wavelength.

1. Radio waves 2. Infrared light 3. Visible light 4. Ultraviolet light 5. X rays 6. Gamma rays

Select the statements below that are true for light waves.

1. The waves travel at about 300,000 kilometers per second in a vacuum. 2. The waves can travel through air and water.

Wavelengths in the microwave portion of the electromagnetic spectrum are comparable in size to which of the following objects?

1. The width of a blade of grass 2. A referee's whistle 3. A soccer ball

Each kind of atom has ____. (Select all that apply.)

1. a unique number of protons in the nucleus 2. a different set of energy levels from any other kind of atom

If you see a planet with a wavelength of maximum emission of 2.9 x 104 nm, then its temperature will be ______ K. (Enter a whole number. Use the version of Wien's law from the book.) Listen to the complete question

100

You observe a blue star and measure its temperature to be 10,000 K. At what wavelength of light is it the brightest?

290 nanometers

Look at the electron orbital diagram. Rank the electronic transitions in order from the smallest (top) to the largest (bottom) amount of energy absorbed.

3-4 2-3 2-4 1-4

In the diagram of the visual spectrum, you would need to place a detector at position number ______ to detect infrared and at position number ______ to detect ultraviolet light.

7 and 1

The image is a solar spectrum. Using measurements of the dark lines, astronomers could determine that ____.

90% of the atoms in the Sun are hydrogen

Three observers at different positions (A, B, C) observe a star moving in the direction of the arrow. Match their positions with the color of Doppler shift they will observe.

A - Redshift B - No shift C - Blueshift

The speed of light in a material is ____ than the speed of light in a vacuum.

Always less

True or false: Redder blackbodies are hotter than bluer ones.

False

Select all the conditions that are the same in the way a continuous and an absorption-line spectrum might be produced and observed.

Hot, dense material is present Light passes through a prism Light with a continuous spectrum is emitted

Select all the information about the Crab Nebula that was learned by observations of radio waves.

It has a pulsar at its center. There are charged particles moving at nearly the speed of light.

Infrared radiation have wavelengths that are ______________ than the wavelengths of red light.

Longer

Which of these wavelength ranges can pass through Earth's atmosphere?

Radio and visible

Which kind of electromagnetic radiation can have wavelengths similar in length to a football field?

Radio waves

Select all the information we can learn by observing emission lines of CN and CO2 from comets.

The molecules exist in gaseous form. Comets contain CN and CO2.

The strength of a spectral line is determined by what two properties?

The number of atoms or molecules radiating and their temperature

Select the properties that astronomers can learn about through studying an object's spectrum.

The temperature of an object The kinds of atoms in an object The quantities of the different atoms in the object

True or false: Astronomers can observe radio waves from interstellar gas clouds.

True

True or false: Short wavelength photons carry more energy than long wavelength ones.

True

Match the wavelength of observations of the Crab Nebula with the information learned from them.

Visible wavelengths -- the speed of gas ejected from the explosion Radio wavelengths -- the pulsation rate of the central star (30 times per second) X ray wavelengths -- the structure of the core

Which property of light determines how much energy electromagnetic radiation carries?

Wavelength

What is the name of the following physical law: As an object's temperature increases, the object radiates light more strongly at shorter wavelengths.

Wien's law

Which types of telescopes must be placed above Earth's atmosphere? (Select all that apply.)

X ray Ultraviolet Gamma ray

The high energy of which kind of electromagnetic radiation allows it to penetrate the soft tissues of your body?

X rays

What kind of electromagnetic radiation has a shorter wavelength than visible and ultraviolet light?

X-rays

The diagram shows electron orbitals for an atom. Arrow A shows what happens when an atom _____ (emits or absorbs) light. Arrow B shows what happens when an atom ______ (emits or absorbs) light.

absorbs; emits

When an atom ____ a photon, an electron moves to an upper orbital and the atom gains energy; when an atom ____ a photon, an electron moves to a lower orbital and the atom loses energy.

absorbs; emits

If you observe light from the extremely hot surface of a star after it passes through the less hot atmosphere of the star, then you will see a(n) _____ spectrum.

absorption-line

Energy levels are ____.

another name for electron orbitals

Atoms are held together by the electrical attraction between ____.

electrons and the nucleus

If you observe light from a very hot, tenuous gas cloud heated by stars close to it, then you will see a(n) ______ spectrum.

emmision-line

When an atom gains energy, the electron moves to a higher orbital, and the atom is said to be

excited

Look at the electron orbital diagram. Which electronic transition would result in the atom emitting a photon with highest energy?

from level 4 to level 2

Arrange the elements in order by how common they are in the Sun, with the most common on top and the least common on bottom.

hydrogen helium oxygen carbon neon

According to the _____, when an atom "loses energy," the energy is not actually lost but is changed into another form, usually a(n) _____.

law of conservation of energy; electromagnetic wave (photon)

Select the two answers to complete this sentence: Electrons have ____ electric charge and are ____ the nucleus in an atom.

negative; attracted to

In order to produce an absorption-line spectrum, light from a source emitting a continuous spectrum must ___.

pass through a cool gas cloud.

The technique used to observe and study a spectrum is called ____

spectroscopy

The _____ of light is measured in meters per second, while the _____ of a photon is measured in joules.

speed & energy

According to Wien's law, a hotter object emits light most strongly at ____ wavelengths and a cooler one emits most strongly at _____ wavelengths.

stronger; longer

We know that cyanogen (CN) and carbon dioxide exist in gaseous form in comets because ____.

these two molecules are detected in emission lines

Compared to visible light ____ has higher energy and ____ has lower energy.

ultraviolet light; infrared radiation