Astronomy Exam 3

 If a material is transparent, then it ________. 

 transmits light well 

 Grass appears green because ________. 

 it reflects green light and absorbs other colors 

 Everything looks red through a red filter because ________. 

 the filter transmits red light and absorbs other colors 

 The wavelength of a wave is ________.

the distance between two adjacent peaks of the wave 

How are wavelength, frequency, and energy related for photons of light? 

Longer wavelength means lower frequency and lower energy. 

Which of the following statements about x-rays and radio waves is true? 

X-rays travel through space at the same speed as radio waves. 

 Red light has a lower energy per photon than blue light. Therefore, red light has ________. 

lower frequency, longer wavelength than blue light 

 Photons behave like ________. 

both waves and particles

What is the overall electrical charge of an atom with 6 protons, 6 neutrons, and 5 electrons? 

+1

An iron atom has an atomic number of 26 and an atomic mass number of 56. If it is neutral, how many protons, neutrons, and electrons does it have? 

26 protons, 30 neutrons, 26 electrons 

Which of the following is an example of reflection or scattering? 

Red light hits a red sweatshirt. 

We can see each other in the classroom right now because we ________. 

reflect visible light

Which statement about photons is true? 

An infrared photon has less energy than an x-ray photon, but travels at the same speed. 

What do we see when white light passes through a cool cloud of gas? 

An absorption line spectrum

When an electron in an atom goes from a higher energy level to a lower energy level, the atom may ________

emit a photon of a specific wavelength 

An electron in an atom can go from a lower energy level to a higher energy level if the atom ________. 

absorbs a photon of a specific wavelength 

Thermal radiation is defined as ________. 

radiation that depends only on the emitting object's temperature 

You are heating two chunks of metal of the same size and shape. One is made of lead and is heated to 400 K. The other is made of iron and is heated to 350 K. Which of the following statements apply to the thermal radiation the two chunks emit? 

The lead spectrum peak is at a shorter wavelength than the iron spectrum peak. 

Suppose you see two stars: a blue star and a red star. Which of the following can you conclude about the two stars? Assume that no Doppler shifts are involved. (Hint: Think about the laws of thermal radiation.) 

The blue star has a hotter surface temperature than the red star. 

We know the Sun is primarily made from hydrogen and helium on the basis of its ________. 

spectrum

 How much of the solar system's total mass is contained in the Sun? 

About 99.8%

 If we could combine all the planets together, their total mass would be about ________ the Sun's mass. 

1/1000 of

 Where does nuclear fusion occur in the Sun? 

Deep in its core

 Which planet has the most extreme differences between its daytime and nighttime temperatures? 

Mercury

 Which planet is most similar in size and mass to Earth? 

Venus

 What is surprising about Earth's Moon? 

It is surprisingly large in comparison to the size of its planet

Which of the following indicates that past conditions on Mars may have been suitable for life? 

There are dried up riverbeds, rock-strewn floodplains, and minerals that form in water. 

The most massive planet in our solar system is ________. 

Jupiter

Which planet has the highest average surface temperature and why? 

Venus, because of its dense carbon dioxide atmosphere

Other than Earth, which of the following has visible polar caps? 

Mars

Which of the following is not an observed pattern of motion in our solar system? 

Most planets orbit the Sun at the same speed

Which of the following is not a characteristic of all the terrestrial planets? 

They have substantial atmospheres

Which of the following is not a characteristic of the jovian planets? 

They have higher average densities than the terrestrial planets. 

Which of the following best described the major ingredients of the jovian planets? 

Hydrogen, helium, and hydrogen compounds 

Where are most asteroids found? 

Between the orbits of Mars and Jupiter

The Oort cloud is _________.

a roughly spherical region larger than the orbit of Pluto that may contain a trillion comets 

Which of the following statements best explains why all the planets orbit the Sun in the same direction and in nearly the same plane? 

The planets formed from a disk of rotating gas, and their orbits therefore orbit as this gas did. 

We know that Earth has water. However, according to our theory of solar system formation, the inner solar system was too hot for hydrogen compounds like water to condense. What do we conclude? 

Earth's water likely was brought here by asteroids or comets that formed beyond the frost line. 

Where did most elements heavier than hydrogen and helium come from? 

They were produced by stars

Have astronomers ever seen a gas cloud that looks like it contains planetary systems that are in the process of forming? 

Yes, there are many such clouds, including the Orion Nebula. 

Which of the following is most important in causing a cloud of gas to collapse to form a star and planets? 

Gravity pulls all the gas inward. 

Why did the solar nebula heat up as it collapsed? 

As it shrank in size, gravitational potential energy was converted to thermal energy. 

If an interstellar gas cloud shrinks in size, what does the law of conservation of energy predict it will do? 

Heat up

According to our theory of solar system formation, which law best explains why the central regions of the solar nebula got hotter as the nebula shrank in size? 

The law of conservation of energy 

Why did the solar nebula flatten into a disk? 

It flattened as a consequence of collisions between particles in the spinning nebula, changing random motions into more orderly ones. 

Which of the following observations of an extrasolar planet system would be inconsistent with what we expect from the nebular theory of solar system formation? 

A system in which all the planets orbit in completely different planes 

What do we mean by the frost line when we discuss the formation of planets in the solar nebula? 

It is a particular distance from the Sun, beyond which the temperature was low enough for ices to condense. 

What happened during the heavy bombardment? 

The planets of the solar system suffered many impacts.