Question 1

The bluer the light,the ____ each photon contains.
A) More energy
B) Less energy
C) Less speed
D) None speed
E) None of the above.

Accepted Answer

Bluer light has a shorter wavelength and higher frequency, which means each photon has more energy according to the equation E=hf, where E is energy, h is Planck's constant, and f is frequency.

Question 2

The Doppler effect states that the motion of any object can
A) shift the wavelength of spectral lines.
B) change the speed of light emitted from the object.
C) enhance the chemical composition of the object.
D) make the object appear hotter.
E) make the object appear cooler.

Accepted Answer

The Doppler effect states that the motion of any object can shift the wavelength of spectral lines. This is why astronomers use it to determine how fast and in which direction celestial bodies are moving.

Question 3

Suppose the laboratory wavelength of a spectral line is 600 nm.In a star it is measured to be 599.4 nm.Is the star moving toward or away from us,relative to the line of sight? How fast is it moving? (Hint: c=300,000 km/s)..
A) toward,300 km/s
B) away,300 km/s
C) at rest,0 km/s
D) sideways,300 km/s
E) toward,150 km/s

Accepted Answer

The star is moving toward us because the observed wavelength (599.4 nm) is shorter than the laboratory wavelength (600 nm), indicating a blueshift. The speed can be calculated using the Doppler shift formula: $v = \frac{\Delta \lambda}{\lambda} \times c = \frac{600 - 599.4}{600} \times 300,000 \, \text{km/s} = 300 \, \text{km/s}$.

Question 4

The two most abundant elements in the sun are
A) nitrogen and oxygen.
B) hydrogen and helium.
C) sulfur and iron.
D) carbon and hydrogen.
E) carbon and nitrogen.

Accepted Answer

Hydrogen and helium are the two most abundant elements in the sun, making up over 98% of its mass.

Question 5

If light from a star passes from an excited low density gas seen against the dark background of space to your telescope and spectroscope,____ spectrum results.
A) a dark (absorption)line
B) a bright (emission)line
C) continuous

Accepted Answer

When light passes through an excited low-density gas, the gas emits light at specific wavelengths, resulting in a bright (emission) line spectrum.

Question 6

Which of the following cannot be determined from the spectrum of a star?
A) chemical composition
B) surface temperature
C) radial (along line of sight)velocity
D) tangential (perpendicular to line of sight)velocity
E) Both c and d

Accepted Answer

The spectrum of a star can determine its chemical composition, surface temperature, and radial velocity through Doppler shifts. However, tangential velocity requires proper motion measurements, not spectral analysis.

Question 7

If a light-emitting object is moving away from you,you observe its wavelengths to be ________ its wavelengths if it were at rest..
A) longer than
B) shorter than
C) the same as

Accepted Answer

This is known as the redshift phenomenon, where the wavelengths appear longer (shifted towards the red end of the spectrum) as the object moves away from the observer.

Question 8

Two white dwarf stars are the same size,but one has a surface temperature twice as hot as the other.The hotter star will radiate ...
A) half as much energy per second as the cooler star.
B) the same amount of energy per second as the cooler star.
C) four times as much energy per second as the cooler star.
D) sixteen times as much energy per second as the cooler star.

Accepted Answer

The luminosity (energy radiated per second) of a star is proportional to the fourth power of its temperature (Stefan-Boltzmann law). Therefore, if one star's surface temperature is twice that of another, it will radiate $2^4 = 16$ times as much energy per second.

Question 9

Which of the following can be determined by using the Doppler Effect? 
A) I & IV
B) II & III
C) II & IV
D) I & III
E) I,III,& IV

Accepted Answer

The answer of Which of the following can be determined...

Question 10

The binding energy of the first level in an atom is 2.2*10 ^- ¹⁸ J,and the binding energy of the second energy level is 1.6*0 ^- ¹⁸ J.What is the energy of the photon that is emitted if an electron moves from the second level to the first? A) 3.3*10^-¹⁸ J B) 3.5*10^-³⁶ J C) 1.4 J D) 3.5*10^-¹⁸ J E) 6.0*10^-¹⁹ J

Accepted Answer

The energy of the photon emitted is the difference in binding energies: 2.2 x 10^-18 J - 1.6 x 10^-18 J = 0.6 x 10^-18 J, which is 6.0 x 10^-19 J.

Question 11

You are standing near a railroad track and a train is moving toward you at 60 mph and blowing his horn.What will you notice as the train moves past you?
A) As the train approaches,the horn will sound lower in pitch than when it is moving away.
B) As the train approaches,the horn will sound higher in pitch than when it is moving away.
C) There will be no change in the pitch of the horn as it moves by.
D) The horn will get louder as the train moves away from me.
E) The horn will get quieter as the train moves toward me

Accepted Answer

As the train approaches, the sound waves are compressed, making the horn sound higher in pitch. As it moves away, the waves are stretched, lowering the pitch. This is known as the Doppler effect.

Question 12

If continuous spectrum light from a star passes through a cool low density gas on its way to your telescope and spectroscope,____ spectrum on the continuous spectrum results.
A) a dark (absorption)line
B) a bright (emission)line
C) continuous

Accepted Answer

When a continuous spectrum light passes through a cool low density gas, it will result in the absorption of certain wavelengths of light by the gas atoms or molecules. This will create dark (absorption) lines in the continuous spectrum where the specific wavelengths of light have been absorbed by the gas. Therefore, the answer is choice A.

Question 13

A very bright UFO is seen near the moon's orbit.An astronomer takes a spectrum of it and discovers it has a bright line spectrum on a dark background.The earth's population is near panic when the astronomer announces the UFO is ...
A) a metal spacecraft.
B) a giant rock about to hit the earth.
C) a glowing cloud of gas.
D) a star like the sun.

Accepted Answer

A bright line spectrum on a dark background is characteristic of an emission spectrum, which is typically produced by a glowing cloud of gas.

Question 14

The H _- line has a wavelength of 434.0 nm when observed in the laboratory.If the H _- line appears in a stars spectrum at 434.5 nm,what is the radial velocity of the star? A) 346 km/sec away from the observer B) 346 km/sec toward the observer C) 1.3*10⁸ m/sec away from the observer D) 1.3*10⁸ m/sec toward the observer E) The radial velocity of the star can not be determined from this information.

Accepted Answer

The observed wavelength is longer than the laboratory wavelength, indicating a redshift. This means the star is moving away from the observer. The radial velocity can be calculated using the formula: v = c * (λ_observed - λ_rest) / λ_rest, where c is the speed of light. Plugging in the values gives approximately 346 km/sec away from the observer.

Question 15

The ____ of a gas is a measure of the average speed of the particles in the gas.
A) heat
B) composition
C) temperature
D) blue shift
E) binding energy

Accepted Answer

Temperature is a measure of the average kinetic energy, or speed, of the particles in a gas.

Question 16

Each element has its own set of characteristic absorption lines because
A) the temperature of each element can varies.
B) elements can exist in different forms of matter.
C) electron energy levels differ for each element.
D) each element has a different mass.
E) absorption lines depend upon the speed of the object.

Accepted Answer

Absorption lines are produced when atoms absorb a specific wavelength of light, which corresponds to the energy needed to lift an electron from one energy level to a higher one. Since each element has a unique number of protons and electrons, their electron energy levels differ, creating a distinct set of absorption lines.

Question 17

What is the order of star colors with increasing temperature?
A) Red,Yellow,Blue
B) Blue,Red,Yellow
C) Red,Blue,Yellow
D) Yellow,Red,Blue
E) Blue,Yellow,Red

Accepted Answer

Red stars are the coolest, followed by yellow stars, and then blue stars, which are the hottest.

Question 18

Which of the following is not a fundamental component of the atom?
A) proton
B) neutron
C) ion
D) electron

Accepted Answer

Protons, neutrons, and electrons are all fundamental components of the atom. Ions, however, are atoms that have gained or lost electrons, resulting in a different number of protons and electrons and therefore a different charge. They are not a fundamental component of the atom itself.

Question 19

The energy of a photon is proportional to the light's
A) wavelength.
B) speed.
C) frequency.
D) intensity.
E) Two of the above.

Accepted Answer

The answer of The energy of a photon is proportional...

Question 20

The diagram illustrates a light source,a gas cloud,and three different lines of sight.Along which line of sight would an observer see an emission spectrum? 
A) 1
B) 2
C) 3
D) 2 and 3
E) none of them

Accepted Answer

The answer of The diagram illustrates a light source,a gas...

Quiz 7: Atoms and Spectra

The bluer the light,the ____ each photon contains.

The Doppler effect states that the motion of any object can

Suppose the laboratory wavelength of a spectral line is 600 nm.In a star it is measured to be 599.4 nm.Is the star moving toward or away from us,relative to the line of sight? How fast is it moving? (Hint: c=300,000 km/s) ..

The two most abundant elements in the sun are

If light from a star passes from an excited low density gas seen against the dark background of space to your telescope and spectroscope,____ spectrum results.

Which of the following cannot be determined from the spectrum of a star?

If a light-emitting object is moving away from you,you observe its wavelengths to be ________ its wavelengths if it were at rest..

Two white dwarf stars are the same size,but one has a surface temperature twice as hot as the other.The hotter star will radiate ...

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

The binding energy of the first level in an atom is 2.210 ^- ¹⁸ J,and the binding energy of the second energy level is 1.60 ^- ¹⁸ J.What is the energy of the photon that is emitted if an electron moves from the second level to the first?

You are standing near a railroad track and a train is moving toward you at 60 mph and blowing his horn.What will you notice as the train moves past you?

If continuous spectrum light from a star passes through a cool low density gas on its way to your telescope and spectroscope,____ spectrum on the continuous spectrum results.

A very bright UFO is seen near the moon's orbit.An astronomer takes a spectrum of it and discovers it has a bright line spectrum on a dark background.The earth's population is near panic when the astronomer announces the UFO is ...

The H _- line has a wavelength of 434.0 nm when observed in the laboratory.If the H _- line appears in a stars spectrum at 434.5 nm,what is the radial velocity of the star?

The ____ of a gas is a measure of the average speed of the particles in the gas.

Each element has its own set of characteristic absorption lines because

What is the order of star colors with increasing temperature?

Which of the following is not a fundamental component of the atom?

The energy of a photon is proportional to the light's

The diagram illustrates a light source,a gas cloud,and three different lines of sight.Along which line of sight would an observer see an emission spectrum?