Mindtap Flashcards:AS101

Identify a similarity between reflecting and refracting telescopes.

Both create images that can be viewed with a lens.

Which of the following can be measured by using the Doppler Effect?

the radial velocity of a star

What is the light-gathering power of a telescope directly proportional to?

the diameter of the primary mirror or lens

________ reach Earth's surface through atmospheric windows.

Visible light waves

Telescopes observing at far-infrared wavelengths:

must be cooled

Suppose the redshifts of four fictional galaxies—Posiedon, Stark, Obeslisk, and Caesar—are 1500 km/s, 78 000 km/s, 6500 km/s, and 18 000 km/s, respectively. Based on the given information, which of the following galaxies is the farthest from Earth?

stark

The ratio of the light-gathering power of Reflecting Telescope 1 with a primary mirror of diameter 10 m to Reflecting Telescope 2 with a primary mirror of diameter 1 m is ________.

100 to 1

Consider the following telescopes. They are identical in every way except in their diameters. Which among the following has the highest resolution power?

Telescope 4 with diameter 2.5 m

What is the longest wavelength of light that can be seen with the human eye?

700 nanometres

Which of the following is a similarity between reflecting and refracting telescopes?

Both form a small, inverted image of an object.

If the average density of matter and energy in the universe is less than the critical density, space-time will be ________.

open

________ is a closely related phenomenon to astronomical seeing.

The twinkling of stars

What is the ratio of the light-gathering power of a telescope with a primary lens of diameter 5 m to a telescope with a primary lens of diameter 2 m?

25 to 4

According to one explanation of Olbers's paradox, the night sky is dark because:

the light from the more distant stars has not yet reached Earth.

What type of telescope is a radio telescope?

reflecting

Which of the following is true of dark energy?

It drives the acceleration of the universe.

If the actual density of your universe were 1.00001 × 10-29 g/cm3 and the critical density were 1 × 10-29 g/cm3, then you would be part of a(n) ________.

flat universe

Which of the following is true of charge-coupled devices (CCDs)?

They can detect both bright and faint objects in a single exposure.

Which of the following is true of an open universe?

It has no centre and no edge.

Which telescope has the largest light-gathering power among the following telescopes?

a telescope of diameter 8 cm and focal length 115 cm

Which of the following has the most light-gathering power?

a telescope of 6 centimetres diameter and focal length of 100 centimetres

The sudden inflation of the universe at the time of the big bang would have:

forced the curvature of the universe toward zero.

The entire electromagnetic spectrum can be divided into the seven types of radiation bands: radio, microwave, infrared, visible, ultraviolet, X-ray, and gamma-ray (from longest to shortest wavelength). To which of the following two bands is Earth's atmosphere most transparent?

visible and radio

Among the following electromagnetic waves, the photons of ________ carry the highest energy.

x-rays

What does the word “radiation” mean when used by scientists?

anything that spreads out from a central source

Which of the following types of electromagnetic radiation is absorbed by ozone in the Earth’s atmosphere?

Ultraviolet Radiation

Which of the following statements about the Earth’s atmosphere is true?

The atmosphere is transparent to most radio waves.

Which of the following is true of light?

It has both wavelike and particlelike properties.

You are standing near a railway track and a train is moving toward you at 100 kph and blowing its whistle. What will you notice as the train moves past you?

As the train approaches, the horn will sound higher in pitch than when the train is moving away.

What is a photon?

aa particle of light

An astronomer takes two pictures of the same object using the Hubble Space Telescope. One picture is taken with red light and one with blue light. Which one would you expect to show finer details?

Blue light

Which of the following statements best describes the wavelength of a wave?

the distance between two adjacent peaks of the wave

What happens to a telescope’s light-gathering power and resolving power when you increase its diameter?

both increase.

The redshifts of two galaxies, Aphrodiety and Ariel Major, are 19 000 km/s and 14 000 km/s, respectively. Based on the given information, it can be concluded that:

Aphrodiety is more distant than Ariel Major.

Which of the following telescopes has the highest magnifying power?

a. Telescope 1, which has a primary lens of focal length 2.5 m and an eyepiece of focal length 1 m

b. Telescope 2, which has a primary lens of focal length 2 m and an eyepiece of focal length 0.5 m

c. Telescope 3, which has a primary lens of focal length 3 m and an eyepiece of focal length 0.8 m

d. Telescope 4, which has a primary lens of focal length 3.5 m and an eyepiece of focal length 2 m

b. Telescope 2, which has a primary lens of focal length 2 m and an eyepiece of focal length 0.5 m

The look-back times for the fictional stars Tetrahedrous and Alpha Centaur are 1.5 years and 3.7 years, respectively. Based on the given information, it can be concluded that:

Tetrahedrous is closer than Alpha Centaur.

Which of the following best explains the concept of atmospheric windows?

Only certain wavelengths of electromagnetic radiation from space reach Earth’s surface.

What type of telescope has a lens as its primary and contains no mirrors?

refracting

What is the relationship between colour and wavelength for light?

Wavelength increases from blue light to red light.

Which of the following is true according to the inflationary universe model?

The universe expanded and cooled until about 10-36 seconds after the big bang.

Joseph, an astronomer, observes different types of radiation through a telescope and records their wavelengths. Radiation 1 has a wavelength of 10-14 m, Radiation 2 has a wavelength of 10-12 m, Radiation 3 has a wavelength of 10-9 m, and Radiation 4 has a wavelength of 10-10 m. In this scenario, Radiation 2 can be classified as ________.

gamma rays

By what factor is the light-collecting power of the James Webb Space Telescope (6. 6 m primary mirror) greater than the light-collecting power of the Hubble Space Telescope (2. 4 m primary mirror)?

7. 56

Identify a true statement about light.

It does not require a medium to travel.

Which of the following is true of reflecting telescopes?

They do not have a lens as the eyepiece.

The fictional stars Gamma Helios, Epsilion Cancer, Alpha Athena Majoris, and Delta Demitri have look-back times of 28 years, 37 years, 81 years, and 72 years, respectively. Based on the given information, we can conclude that the farthest star is ________.

Alpha Athena Majoris

the Hubble Space Telescope (HST) is not affected by _______

seeing distortions.

An interferometer has a resolving power equal to that of a telescope as large as:

the maximum separation between the individual telescopes.

Which of the following types of electromagnetic radiation is absorbed by water lower in the Earth’s atmosphere, but can be detected by telescopes that are on mountaintops or are carried by aircraft?

infrared radiation

What type of primary is found in a reflecting telescope?

mirror

Unlike sound, light:

can travel through a vacuum

In the context of a big bang model, what is the flatness problem?

why was the universe so close to exactly flat, with no space-time curvature, at the time of the big bang?

what is true of the big rip?

Even if it is in the future, nothing will be happening for at least 30 billion years.

Why do astronomers build telescopes on tops of mountains?

there is less air to dim the light

The magnifying power of a telescope with a primary lens of focal length 2 m and an eyepiece of focal length 0.05 m is ________.

40

Which of the following factors does the escape velocity from the surface of an object depend on?

object’s mass and radius

Where are red giant stars found in the Hertzsprung-Russell diagram?

above the main sequence

Which statement best describes why stars eventually die?

they exhaust all their fuel

The densest stars in the Hertzsprung-Russell diagram are the white dwarf

True or False?

true

What is the Schwarzschild radius?

the distance between the centre of a black hole and its event horizon

If a star is twice as hot as the Sun and only half the Sun's diameter, it will be less luminous than the Sun.

True or false?

false

If you compare two stars, which one will always have the greater luminosity?

The one with the smaller absolute magnitude will always have the ______ luminosity.

greater

While on the main sequence, what is a star’s primary energy source?

nuclear fusion

black holes:

Any event that occurs inside the event horizon is _____ to outside observers.

invisible

What is most similar in size to a brown dwarf?

planet Jupiter

Why are star clusters important to our study of stars?

because they allow us to test our theories and models of stellar evolution

Which technique was used to capture the first-ever image of a black hole?

interferometry

A certain star moves from the middle toward the top right of the Hertzsprung–Russell diagram. How is the star changing?

It is getting larger and cooler.

Black holes:

a. originate from the death of stars that have low masses.

b. are funnel shaped.

c. appear to have a strong gravitational field only when one ventures too close to it.

d. have paths that lead objects in and out of it, enabling light to escape out easily.

c. appear to have a strong gravitational field only when one ventures too close to it.

To demonstrate a mode of energy transfer, Jeremy asked one of his fellow students to put his hand 10 centimetres from one side of the flame. Although the student was not touching the flame, he could still feel the heat. It is evident that the majority of energy transferred from the flame to the student's hand took place by ________.

Radiation

What statement is true of a white dwarf?

It has exhausted its hydrogen and helium fuel and produced carbon and oxygen.

Your feet get cold when you stand on a cold floor.

this is the best example of energy transport by __________?

conduction

What force is responsible for the collapse of an interstellar cloud?

gravity

What has greater density than a white dwarf?

a neutron star

What characteristic of a star primarily determines its location on the main sequence?

mass

If two stars are emitting the same amount of light, how will the star that is farther away appear?

dimmer

Which of the following is an example of time dilation?

As a star approaches a black hole’s event horizon, it appears to move more and more slowly.

The luminosity of a star is the total amount of energy it radiates each second.

true or false?

true

You are asked to calculate the escape velocity for a white dwarf. What information do you need in order to complete your calculation?

the object’s mass and radius

what statement is true of main-sequence stars?

The more massive a star is, the more luminous it is.

what is the most important factor that determines a life cycle of a star (for example, why some stars have a short life span)?

mass

Why do astronomers sometimes say “black holes don’t suck”?

A black hole’s gravity is the same as that of any other object of the same mass.

What is the ultimate fate of our Sun?

It will become a white dwarf.

What aspect of a star is a measure of the total energy radiated by the star in one second?

luminosity

Which of the following has a radius of about 10 kilometres and is supported by the pressure associated with degenerate neutrons?

neutron star

Why do white dwarfs have very low luminosities?

They are very small.

An isolated black hole is totally invisible because:

nothing can escape from an event horizon.

The nearest star, Proxima Centauri, is about four light-years away and has a luminosity about 0.001 times that of the Sun. If Proxima Centauri were at a distance of one light-year instead of four, how much brighter would it appear in the sky?

16 times brighter

In a Hertzsprung-Russell diagram, where are 90 percent of all the stars found?

on the main sequence

To demonstrate a mode of energy transfer, Jeremy held an iron rod over the flame of a burner until the rod became too hot to hold with his bare hands. The heat was finally transferred from the hot gas to the rod by ________.

conduction

Absolute magnitude is defined as the apparent magnitude that a star would have if observed at a distance of 33 light-years. Consider a star at a distance of 350 light-years that has an apparent magnitude of +5. What would its absolute magnitude be?

less than +5

Which of the following lists objects in order of increasing size?

a. a solar-mass black hole, Earth, a neutron star

b. Earth, a neutron star, a solar-mass black hole

c. Earth, a solar-mass black hole, a neutron star

d. a solar-mass black hole, a neutron star, Earth

d. a solar-mass black hole, a neutron star, Earth

What is the approximate size of the Schwarzschild radius of a one solar mass black hole?

3 kilometers

What is the term that describes the slowing of clocks in strongly curved space-time?

time dilation

What properties of a star determine its luminosity?

Temperature and diameter

What is the name of the process by which the Sun turns mass into energy?

Nuclear fusion

Where is the singularity of a black hole found?

within the event horizon

Unlike Mercury, Mars has ________.

moons

what statement is true of the solar system?

Nearly all the moons in the solar system orbit around their respective planets.

The statement "The albedo of a planet is 0.75" implies that the planet:

reflects only 75 percent of the light that hits it.

How do we know that extra solar planets are orbiting other stars?

We see a star's light dim as a planet passes in front of the star.