Spectra







according to Kirchoff's rules planets will radiate which kind of spectrum?

A continuous.

B emission.

C absorption.

D none because planets are not hot enough to radiate.



according to Kirchoff's rules hot luminous solids emit what kind of spectra?

A continuous spectra.

B emission spectra.

C synchrotron like spectra.

D absorption.



light emitted by an atom after an absorption can never have

A a shorter wavelength

B the same wavelength

C a longer wavelength

D a lower frequency



the uniqueness of the spectral line pattern of any element is caused by

A the temperature conditions under which that element is formed

B the energy level structure of the element

C the pressure of gas in the stellar atmosphere

D the Doppler shift



the wavelength of light reemitted after an absorption on the average has

A shorter wavelength

B longer wavelength

C the same wavelength

D an unpredictable wavelength



whenever an electron in an atom moves from an outer to an inner orbit

A a light wave is emitted

B a light wave is absorbed

C a chemical reaction occurs

D a laser wave is created



a continuous spectrum results when

A two atoms interact

B a photon interacts with another atom

C a large number of atoms interact

D all of the above



each element has its own characteristic spectrum because

A the speed of light differs for each element.

B some elements are at a higher temperature than others.

C atoms combine to form molecules, releasing different wavelengths depending on the elements involved.

D electron energy levels are different for different elements.

E hot solids, such as tungsten, emit a continuous spectrum.



which of the following could not explain why hydrogen lines are not seen in the spectrum of a certain star

A the star is too hot

B the star is too cool

C there is little hydrogen in the star

D the pressure is too great



photons produced by two electrons dropping from one orbit to the same small orbit will have the same

A frequency

B wavelength

C energy

D all of the above



a bright line spectrum results when an electron in an atom

A moves around the nucleus in an orbit

B moves away from the nucleus

C moves toward the nucleus

D is absorbed by the nucleus



photons reemitted after an absorption can never have

A the same wavelength as the original photon

B longer wavelength than the original photon

C shorter wavelength than the original photon

D the same frequency as the original.



a dark line in a spectrum is formed when an electron in an atom moves

A to an outer orbit

B to an inner orbit

C out of the atom completely

D to the other side of the atom in the same orbit



which of the following characteristics of a star will cause absorption lin to be shifted, but not broadened?

A motion of the star towards or away from us

B rotation of the star on its axis

C high gas pressure in the star

D motion of the star perpendicular to the line of sight



collisions between atoms can result directly in the

A emission of a light wave

B the absorption of a light wave

C fission of the atom

D excitation of an electron in an atom



a dark line spectrum is produced when an electron

A makes a transition from an inner to an outer orbit in an atom

B is stripped entirely from the atom

C makes a transition from an outer to an inner orbit in an atom

D is exchanged from one atom to another



a star of low surface temperature surrounded by a higher temperature rarefied cloud of gas would show a

A continuous spectrum only

B dark line spectrum only

C bright line spectrum possibly along with an ordinary stellar spectrum

D no spectrum at all



in the laboratory, I am looking at a hot glowing object through a tube than has some cool gas in it. I will see

A just a continuous spectrum

B a continuous spectrum with some absorption lines

C a continuous spectrum with some emission lines

D a spectrum with only emission lines in it



which of the following is the most common type of stellar spectrum

A dark line

B bright line

C continuous

D white



light remitted after an absorption will usually have

A a longer wavelength than the original

B a shorter wavelength than the original

C a higher frequency than the original

D a greater intensity than the original



most stars have spectra showing dark lines against a continuous background of color. according to Kirchoff's rules, this observation means that

A most stars are made of hot, thin gas.

B most stars are made of cool, thin gas.

C light from a cool, thin part of a star passes through a region of hotter, thin gas.

D light from a dense, hot part of a star passes through a region of cooler gas.

E light from a dense, hot part of a star passes through a region of even hotter gas.



a bright line spectrum is

A obtained when a continuous spectrum shines through a low pressure gas

B emitted by a low pressure gas

C emitted by a solid

D obtained when a continuous spectrum shines through a high pressure gas.



if you observe a neon advertising sign through a spectroscope, you would expect to see a

A continuous spectrum.

B dark-line (absorption) spectrum

C bright-line (emission) spectrum.

D no spectrum at all because the neon is in glass.



a dark line spectrum results when an electron in an atom

A moves toward the nucleus

B moves around the nucleus in an orbit

C moves away from the nucleus

D is absorbed by the nucleus.



normally a solid emits

A a continuous spectrum

B a dark line spectrum

C a bright line spectrum

D no spectrum



spectral lines are observed because

A only certain photons can exist

B only certain electron orbits can exist

C our equipment only detects certain wavelengths

D different electrons give off different wavelengths



the visible series of hydrogen lines, when seen in absorption, is due to electrons

A initially in the ground state

B which make a transition to the ground state

C initially in the second allowed orbit

D which make a transition to the second allowed orbit



ordinarily, a photon reemitted after an absorption will never have

A a longer wavelength than the original photon

B the same wavelength as the original photon

C a shorter wavelength than the original photon

D the same energy as the original photon



the visible spectrum received from the sun is of which type?

A continuous.

B emission.

C synchrotron.

D absorption.



when you see a spectrum with absorption lines in it, you can infer that

A the light passed through ionized atoms.

B electrons moved up in energy levels to absorb the light.

C electrons moved down in energy levels to absorb the light.

D all the atoms were in excited states.

E all the atoms were of the same element.



the hydrogen Balmer lines are weak in the spectra of cool stars because most of the hydrogen atoms have their electrons in the

A fourth orbit.

B third orbit.

C second orbit.

D ground state.



the lines of hydrogen are prominent in the spectra of stars

A almost always

B only in the hottest stars

C only in the coolest stars

D only in moderately hot stars



a dark line spectrum occurs when

A only certain wavelengths are absorbed by the atoms

B only certain wavelengths are emitted by the atoms

C the atoms are packed very close together

D collisions between the atoms are very violent



a bright line spectrum will be emitted by a glowing

A solid

B liquid

C gas under high pressure

D gas under low pressure



an electron can be excited in an atom by

A emitting a light wave

B a violent collision with another atom

C a nuclear reaction within an atom

D a spontaneous transition to an outer orbit.



if you view the light from an transparent, hot gas through a spectroscope, you would expect to see what kind of spectrum?

A continuous

B emission line.

C absorption line.

D combination of emission line and continuous.

E combination of absorption line and continuous.



dark lines in a stellar spectrum represent

A divisions between different colors

B specified transitions of electrons in atoms

C discrete motions of the star

D physically dis-allowed photons



absorption of a visible light photon by an atom involves

A a nuclear change

B an outward transition by an electron

C an inward transition by an electron

D a collision between two atoms



the Doppler shift in stellar spectra

A is caused by the object's movement perpendicular to the line of sight

B is caused by optical aberrations in equipment

C is caused by the changing speed of light as the radiation from distant objects comes through space

D is caused by movement toward and away from the observer



lines in spectra are important because they

A allow you to identify the kind of material forming the spectra

B present striking black and white pictures

C allow you to identify the colors present within the spectra

D no choice



the "color" of the radiation an electron emits when it makes a transition in an atom depends only on:

A the energy of its initial state.

B the energy of its final state.

C the difference in the energies of its initial and final states.

D the density of the gas.



a glowing gas under low pressure will show a

A continuous spectrum

B bright line spectrum

C dark line spectrum

D no choice



visible absorption lines of hydrogen are not always present in a star's spectrum because

A they must end with an electron in the second orbit

B they must begin with an electron in the second orbit

C many stars do not have enough hydrogen

D they must begin with a free electron and a hydrogen nucleus



to produce an absorption line, an electron in an atom must

A go up in energy levels.

B drop down in energy levels.

C stay in the same energy level.

D escape the atom completely.



the normally observed spectrum of the sun is a

A bright line spectrum

B dark line spectrum

C continuous spectrum

D none of the above



for visible light, ordinary glass is a good

A absorber

B emitter

C reflector

D transmitter



the early workers of spectroscopy discovered which very significant fact about the spectra produced by hot gases, such as elements heated in a flame

A chemical elements emit spectral lines which move continuously towards the blue end of the spectrum as the gas temperature increases

B hot gases produce a continuous spectrum with no observable features or lin

C all chemical elements produce the same set of spectral lines, and are hence indistinguishable

D each chemical element produces its own characteristic pattern of spectral lines



the hydrogen line spectrum is not visible in very hot stars because

A hydrogen is not present in those stars

B the electron has been stripped from the atom in most hydrogen atoms

C all the electrons are in the ground state, incapable of producing visible lines

D the dark lines are filled in by other photons.



a dark line spectrum results when electrons in atoms

A move toward the nucleus

B move around the nucleus in an orbit

C move away from the nucleus

D are absorbed by the nucleus



a dark line spectrum is observed when white light passes through a gas because

A only certain electron orbits are allowed

B the light heats up the gas and causes more collisions

C some wavelengths are always missing from white light

D electrons always try to be in the lowest orbit



when an electron moves from an outer orbit to an inner orbit it

A loses energy

B gains energy

C absorbs a light wave

D changes the atom into a different element



which of the following is produced when white light is shined through a cool gas?

A an absorption spectrum.

B a continuous spectrum.

C an emission spectrum.

D all of the above.

E none of the above.



atoms of a given element

A emit or absorb photons of characteristic wavelengths

B have absorption spectra with characteristic bright lines

C have emission spectra with characteristic dark lines

D none of the above



a continuous spectrum results when

A many different types of atoms are present

B atoms are pushed close together

C several electrons within an atom make transitions

D the electrons are removed from the atoms



in general, the observed spectra of stars appear as what kind of

A absorption.

B emission.

C continuous.

D nonthermal.



a hot rarefied gas emits what kind of spectrum?

A a continuous spectrum.

B an emission spectrum.

C a synchrotron like spectrum.

D an absorption spectrum.



a cloud of gas located directly between a light source and the observer will produce

A a continuous spectrum.

B an absorption spectrum.

C an emission spectrum.

D none of these.



which of the following is not a correct statement

A a light wave must either be completely absorbed or not changed at all

B only a certain number of vacancies are allowed in an orbit at one time

C only certain electron orbits are allowed

D electrons must always be in the lowest allowed orbit



an electron moving to an outer orbit may be

A emitting light

B absorbing light

C reflecting light

D transmitting light



the solar spectrum is which of the following?

A an absorption spectrum.

B a continuous spectrum.

C an emission spectrum.

D all of the above.

E none of the above.



the Doppler effect

A is a measure of a star's space velocity

B is a shift of the star's spectrum which depends on its velocity in the lin of sight

C is a shift in the stars apparent position with respect to background stars

D is a shift in the star's spectrum which depends on its temperature



the direction of a photon emitted after absorption is

A completely random

B the same as the absorbed photon

C opposite to the absorbed photon

D no choice



which of the following cannot result in the excitation of an electron from the ground state of an atom

A a collision with another atom

B collision with an electron

C absorption of a photon

D emission of a photon?



an electron making an outward transition in an atom has

A absorbed a photon

B emitted a photon

C emitted a stimulated photon

D emitted an imaginary photon



absorption of light waves by electrons in atoms results in a

A continuous spectrum

B bright line spectrum

C dark line spectrum

D can't tell which type of spectrum without more information



a photon emitted after an absorption can never

A travel in the same direction

B have a shorter wavelength

C have a longer wavelength

D travel in the opposite direction



electrons can not be excited by

A collision

B emitting a light wave

C absorbing a light wave

D a chemical reaction



to produce an emission line, an electron in an atom must

A go up in energy levels.

B drop down in energy levels.

C stay in the same energy level.

D escape the atom completely.



if you see a continuous spectrum with a spectroscope, you know that the source of the spectrum is

A a cool, transparent gas.

B a hot, transparent gas.

C a hot, opaque, solid, liquid, or gas.

D none of the above.



atoms in a hot gas emit a spectrum which is

A continuous over all visible wavelengths, with maximum intensity in the blue

B a series of specified colors, unique to the type of atom in the tube, but fixed in position when gas temperature changes

C a series of specific colors, which change in position as the gas temperature is changed

D a series of specific colors at the same wavelengths, independent of the type of atom excited



by the word spectrum we mean

A the spreading of light into its component colors

B the distribution of electromagnetic energy as it varies with wave length

C a graph showing the amount of electromagnetic energy a body emits at different wavelengths

D all of the above



you observe light from the sun with a spectroscope. what do you see?

A bright lines against a dark background

B a continuous spectrum with no lines

C a continuous spectrum with bright lines

D a continuous spectrum with dark lines



the specific colors of light emitted by an atom in a hot thin gas are caused by

A electrons dropping in towards the nucleus through specific orbits, losing energy as they do so

B an electron dropping into the nucleus, producing small nuclear changes

C the vibrations of the nucleus within the atom

D the vibrations of the electrons within the atom



a cloud of gas located directly between a light source and the observer will produce

A a continuous spectrum

B a dark line spectrum

C a bright line spectrum

D none of these



an atom in an excited state

A can emit a photon and go to a lower energy state

B can absorb a photon and return to the ground state

C will eventually eject an electron

D will collapse into a nucleus



spectral lines are formed because

A only certain types of photons are allowed to exist

B only certain electron orbits are allowed in atoms

C the Doppler effect causes all photons to be shifted to a particular wavelength

D no choice



how do astronomers know that elements such as iron are present in the sun and other stars?

A we can test samples of the sun and other stars in laboratories on Earth

B much of the Earth is iron; therefore, much of the sun and other stars must be iron

C the sun and other stars are more massive than Earth; therefore, they must contain heavy elements such as iron

D dark lines are observed in the sun's spectrum that match those bright line produced by iron on Earth



a glowing, low-pressure gas produces what type of spectrum?

A continuous

B absorption (dark line)

C emission (bright line)

D reflection



spectral lines unique to each type of atom are caused by

A each atom having a unique set of protons

B each element having the unique sets of electron orbits

C each type of photon emitted by the atom being unique

D none of the above; spectral lines are not unique to each type of atom



atoms in a thin, hot gas emit light

A at all wavelengths, with the distribution depending upon the temperature o the gas

B only at a specific single wavelength

C only at visible wavelengths

D at very specific wavelengths, the pattern depending upon the type of atom



if you look at a very dense and hot gas through a volume of much cooler, tenuous gas, you will see

A a dark-line spectrum

B a bright-line spectrum

C a continuous spectrum

D both a dark-line and a bright-line spectrum



if a star is moving towards us, its speed can be determined by measuring I

A red shift

B Doppler shift

C parallax shift

D photons' speed



discrete spectral lines are observed from a single element because

A our equipment only detects certain wavelengths

B different electrons contain different wavelengths

C only certain wavelengths can exist

D only certain electron orbits can exist



an electron which makes an inward transition in an atom is

A exchanging position with another electron

B colliding with another atom

C emitting a light wave

D absorbing a light wave



you observe light from the sun with a spectroscope. what do you see?

A bright lines against a dark background.

B a continuous spectrum with no lines.

C a continuous spectrum with bright lines.

D a continuous spectrum with dark lines.



an atom whose electrons are in the smallest orbits possible

A can emit a photon

B can absorb a photon

C cannot make any transitions

D either a or b



which element was found in the sun before it was found on the Earth?

A helium

B hydrogen

C calcium

D sodium



the dark line spectrum of the sun comes from the

A interior

B photosphere

C chromosphere

D no choice



an important characteristic of an atom in a laser is that it

A has a large number of electrons for stimulation

B have its electrons in the ground state

C have a long-lived excited state

D have lots of vacancies available



according to Kirchoff's laws, a hot low pressure gas gives off a spectrum which is

A continuous

B dark line

C bright line

D both dark and bright line



a low pressure high temperature gas gives off a

A bright line spectrum

B dark line spectrum

C continuous spectrum

D a red shifted dark line spectrum



the fraunhofer lines are ______ in the sun's spectrum

A dark lines

B bright lines

C gaps

D no choice



a red shirt

A absorbs red light

B emits red light

C absorbs all colors but red

D is hotter than a blue shirt



a blue shirt absorbs

A mostly blue light

B all colors but blue

C no colors

D all colors



a solid will always give off a(n)

A dark line spectrum

B bright line spectrum

C continuous spectrum

D ultraviolet spectrum



an important characteristic of laser light is that all the photons

A travel in the same direction

B have the same frequency

C oscillate together

D all of the above



the important property of a helium atom that makes it useful in a laser is

A it has appropriately spaced energy levels

B it has a vacancy in the necessary orbit

C electrons can get trapped for relatively long times in an excited state

D it's easy to excite the electrons



molecular bands represent

A a fundamentally different type of absorption process from atomic absorption lines

B transitions of atoms within the molecule

C transitions of atoms between molecules

D individual lines due to transitions by electrons which are so close together that they are indistinguishable



which type of spectrum does a liquid produce

A bright line

B dark line

C continuous

D Doppler?



which type of spectrum requires a two step process

A bright line

B dark line

C continuous

D Doppler?



a continuous spectrum should be obtained from

A an individual atom

B a collection of very many non-interacting atoms

C two interacting atoms

D a collection of very many interacting atoms



the most likely explanation of an astronomical spectrum that contains both molecular lines and helium lines is

A quasar

B neutron star

C black hole capturing matter

D binary star



which of the following is not necessary to operate a laser

A an atom with a metastable state

B a group of atoms with a population inversion

C an ordinary source of light

D the action of the Doppler effect?



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