Question 1

How does the speed of light traveling through a medium (such as air or glass)compare to the speed of light in a vacuum?

Accepted Answer

A) It is the same as the speed of light in a vacuum. 
B) It is always less than the speed of light in a vacuum. 
C) It is always greater than the speed of light in a vacuum. 
D) Sometimes it is greater than the speed of light in a vacuum,and sometimes it is less,depending on the medium. 
E) Light can't travel through a medium,it only can go through a vacuum. 
A) It is the same as the speed of light in a vacuum. 
B) It is always less than the speed of light in a vacuum. 
C) It is always greater than the speed of light in a vacuum. 
D) Sometimes it is greater than the speed of light in a vacuum,and sometimes it is less,depending on the medium. 
E) Light can't travel through a medium,it only can go through a vacuum.

Question 2

Einstein showed that the _________ could be explained if photons carried quantized amounts of energy.

Accepted Answer

A) warping of space and time 
B) Heisenberg uncertainty principle 
C) photoelectric effect 
D) theory of special relativity 
E) Bohr model of the atom 
A) warping of space and time 
B) Heisenberg uncertainty principle 
C) photoelectric effect 
D) theory of special relativity 
E) Bohr model of the atom

Question 3

A spaceship is traveling toward Earth while giving off a constant radio signal with a wavelength of 1 meter.What will the signal look like to people on Earth?

Accepted Answer

A) a signal with a wavelength less than 1 m 
B) a signal with a wavelength more than 1 m 
C) a signal moving faster than the speed of light 
D) a signal moving slower than the speed of light 
E) a signal with a wavelength of 1 m,moving the normal speed of light 
A) a signal with a wavelength less than 1 m 
B) a signal with a wavelength more than 1 m 
C) a signal moving faster than the speed of light 
D) a signal moving slower than the speed of light 
E) a signal with a wavelength of 1 m,moving the normal speed of light

Question 4

What does it mean to say that an object is in thermal equilibrium?

Accepted Answer

A) It isn't absorbing any energy. 
B) It isn't radiating any energy. 
C) It is radiating more energy than it is absorbing. 
D) It is absorbing more energy than it is radiating. 
E) It is absorbing the same amount of energy that it is radiating. 
A) It isn't absorbing any energy. 
B) It isn't radiating any energy. 
C) It is radiating more energy than it is absorbing. 
D) It is absorbing more energy than it is radiating. 
E) It is absorbing the same amount of energy that it is radiating.

Question 5

What is the difference between visible light and X-rays?

Accepted Answer

A) Speed;X-rays go faster than visible light. 
B) Speed;X-rays go slower than visible light. 
C) Wavelength;X-rays have a shorter wavelength than visible light. 
D) Wavelength;X-rays have a longer wavelength than visible light. 
E) X-rays are made up of particles,while visible light is made up of waves. 
A) Speed;X-rays go faster than visible light. 
B) Speed;X-rays go slower than visible light. 
C) Wavelength;X-rays have a shorter wavelength than visible light. 
D) Wavelength;X-rays have a longer wavelength than visible light. 
E) X-rays are made up of particles,while visible light is made up of waves.

Question 6

As a blackbody becomes hotter,it also becomes _________ and _________.

Accepted Answer

A) more luminous;redder 
B) more luminous;bluer 
C) less luminous;redder 
D) less luminous;bluer 
E) more luminous;stays the same color 
A) more luminous;redder 
B) more luminous;bluer 
C) less luminous;redder 
D) less luminous;bluer 
E) more luminous;stays the same color

Question 7

Describe,in your own words,the fundamental problem with the Bohr model of the atom.(That is,why doesn't an electron orbit a nucleus like a planet does the Sun?)

Accepted Answer

In this model,the electron is constantly

Question 8

Why is an iron atom a different element than a carbon atom?

Accepted Answer

A) A carbon atom has fewer neutrons in its nucleus than an iron atom. 
B) An iron atom has more protons in its nucleus than a carbon atom. 
C) An iron atom has more electrons than a carbon atom. 
D) A carbon atom is bigger than an iron atom. 
E) All of the above are true. 
A) A carbon atom has fewer neutrons in its nucleus than an iron atom. 
B) An iron atom has more protons in its nucleus than a carbon atom. 
C) An iron atom has more electrons than a carbon atom. 
D) A carbon atom is bigger than an iron atom. 
E) All of the above are true.

Question 9

How much would you have to change the temperature of an object if you wanted to increase its flux by a factor of 100?

Accepted Answer

Because flux is proportional t

Question 10

The n = 5 electronic energy level in a hydrogen atom is 1.5 × 10−19 J higher than the n = 3 level.If an electron moves from the n = 5 level to the n = 3 level,then a photon of wavelength:

Accepted Answer

A) 1.3 nm,which is in the ultraviolet region,is emitted 
B) 1.3 nm,which is in the ultraviolet region,is absorbed 
C) 1,300 nm,which is in the infrared region,is absorbed 
D) 1,300 nm,which is in the infrared region,is emitted 
E) no light will be absorbed or emitted 
A) 1.3 nm,which is in the ultraviolet region,is emitted 
B) 1.3 nm,which is in the ultraviolet region,is absorbed 
C) 1,300 nm,which is in the infrared region,is absorbed 
D) 1,300 nm,which is in the infrared region,is emitted 
E) no light will be absorbed or emitted

Question 11

If you observe a star,you will see:

Accepted Answer

A) an absorption spectrum 
B) a continuous spectrum 
C) an emission spectrum 
D) a rainbow spectrum 
E) a dark spectrum 
A) an absorption spectrum 
B) a continuous spectrum 
C) an emission spectrum 
D) a rainbow spectrum 
E) a dark spectrum

Question 12

Imagine you see a streetlamp that is 100 meters away from you and is 10,000 times more luminous than a firefly.How close would you have to be to the firefly to make it look as bright as the streetlamp?

Accepted Answer

For objects with equal brightn

Question 13

Compare two blackbody objects,one at 200 K and one at 400 K.How much larger is the flux from the 400 K object,compared to the flux from the 200 K object?

Accepted Answer

A) two times larger 
B) four times larger 
C) eight times larger 
D) sixteen times larger 
E) They have the same flux. 
A) two times larger 
B) four times larger 
C) eight times larger 
D) sixteen times larger 
E) They have the same flux.

Question 14

If you were driving down a deserted country road and you saw a light in the distance,what would you need to measure or know about it in order to calculate how far away it was?

Accepted Answer

You would need to kn

Question 15

You are driving on the freeway when a police officer records a shift of −7 nm when he or she hits you with a radar gun that operates at a wavelength of 0.1 m.How fast were you going?

Accepted Answer

A) 43 mph 
B) 83 mph 
C) 21 mph 
D) 65 mph 
E) 47 mph 
A) 43 mph 
B) 83 mph 
C) 21 mph 
D) 65 mph 
E) 47 mph

Question 16

Which of these stars would have the biggest redshift?

Accepted Answer

A) a star moving slowly toward you 
B) a star moving fast toward you 
C) a star moving slowly away from you 
D) a star moving fast away from you 
E) a star that is not moving away from you or toward you 
A) a star moving slowly toward you 
B) a star moving fast toward you 
C) a star moving slowly away from you 
D) a star moving fast away from you 
E) a star that is not moving away from you or toward you

Question 17

If you find that the H-alpha line in a star's spectrum occurs at a wavelength of 656.45 nm,what is the star's radial velocity? Note that the rest wavelength of this line is 656.30 nm.

Accepted Answer

A) 150 km/s away from you 
B) 150 km/s toward you 
C) 350 km/s toward you 
D) 70 km/s away from you 
E) 70 km/s toward you 
A) 150 km/s away from you 
B) 150 km/s toward you 
C) 350 km/s toward you 
D) 70 km/s away from you 
E) 70 km/s toward you

Question 18

Name four physical properties of an object that we can determine by analyzing the radiation that it emits,and briefly describe how these properties are determined.Cite the names of any laws that apply.

Accepted Answer

We can learn the following: (1)measure t

Question 19

Light is:

Accepted Answer

A) a wave 
B) a particle 
C) both a particle and a wave 
D) neither a particle nor a wave 
A) a wave 
B) a particle 
C) both a particle and a wave 
D) neither a particle nor a wave

Question 20

Star C and star D have the same luminosity.Star C is twice as far away from Earth as star D.How do the brightnesses of stars C and D compare?

Accepted Answer

A) Star C appears four times as bright as star D. 
B) Star C appears twice as bright as star D. 
C) Star D appears twice as bright as star C. 
D) Star D appears four times as bright as star C. 
E) Stars C and D appear equally bright. 
A) Star C appears four times as bright as star D. 
B) Star C appears twice as bright as star D. 
C) Star D appears twice as bright as star C. 
D) Star D appears four times as bright as star C. 
E) Stars C and D appear equally bright.

Exam 5: Light

How does the speed of light traveling through a medium (such as air or glass)compare to the speed of light in a vacuum?

Einstein showed that the _________ could be explained if photons carried quantized amounts of energy.

A spaceship is traveling toward Earth while giving off a constant radio signal with a wavelength of 1 meter.What will the signal look like to people on Earth?

What does it mean to say that an object is in thermal equilibrium?

What is the difference between visible light and X-rays?

As a blackbody becomes hotter,it also becomes _________ and _________.

Describe,in your own words,the fundamental problem with the Bohr model of the atom.(That is,why doesn't an electron orbit a nucleus like a planet does the Sun?)

Why is an iron atom a different element than a carbon atom?

How much would you have to change the temperature of an object if you wanted to increase its flux by a factor of 100?

The n = 5 electronic energy level in a hydrogen atom is 1.5 × 10−19 J higher than the n = 3 level.If an electron moves from the n = 5 level to the n = 3 level,then a photon of wavelength:

If you observe a star,you will see:

Imagine you see a streetlamp that is 100 meters away from you and is 10,000 times more luminous than a firefly.How close would you have to be to the firefly to make it look as bright as the streetlamp?

Compare two blackbody objects,one at 200 K and one at 400 K.How much larger is the flux from the 400 K object,compared to the flux from the 200 K object?

If you were driving down a deserted country road and you saw a light in the distance,what would you need to measure or know about it in order to calculate how far away it was?

You are driving on the freeway when a police officer records a shift of −7 nm when he or she hits you with a radar gun that operates at a wavelength of 0.1 m.How fast were you going?

Which of these stars would have the biggest redshift?

If you find that the H-alpha line in a star's spectrum occurs at a wavelength of 656.45 nm,what is the star's radial velocity? Note that the rest wavelength of this line is 656.30 nm.

Name four physical properties of an object that we can determine by analyzing the radiation that it emits,and briefly describe how these properties are determined.Cite the names of any laws that apply.

Light is:

Star C and star D have the same luminosity.Star C is twice as far away from Earth as star D.How do the brightnesses of stars C and D compare?

Why Learn Astronomy

Patterns in the Skymotions of Earth

Motion of Astronomical Bodies

Gravity and Orbits

The Tools of the Astronomer

The Birth and Evolution of Planetary Systems

The Terrestrial Planets and Earths Moon

Atmospheres of the Terrestrial Planets

Worlds of Gas and Liquid the Giant Planets

Planetary Adornments Moons and Rings

Dwarf Planets and Small Solar System Bodies

Taking the Measure of Stars

Our Starthe Sun

Star Formation and the Interstellar Medium

Evolution of Low-Mass Stars

Evolution of High-Mass Stars

Relativity and Black Holes

The Expanding Universe

Galaxies

The Milky Waya Normal Spiral Galaxy

Modern Cosmology

Large-Scale Structure in the Universe

Life

Filters

As a blackbody becomes hotter,it also becomes _ and _.

The n = 5 electronic energy level in a hydrogen atom is 1.5 × 10⁻¹⁹ J higher than the n = 3 level.If an electron moves from the n = 5 level to the n = 3 level,then a photon of wavelength: