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Radiochemistry and Nuclear Chemistry self-test # 17

Comprises Chapter 17

This is a self grading test of your knowledge. It consists of 20 randomly chosen questions with single or multiple answers. The questions with single answers have round buttons and the questions with perhaps more than one correct answer have square buttons. Answer the questions by clicking on the corresponding button in the list of alternative answers. On questions with a single answer (round buttons to click on), it is only possible to mark one of the alternative answers as correct.
Grading of the completed test is automatic when you click on the button marked "GRADE MY ANSWERS" at the end of the test.
Correct answers can be read by clicking on the button having the same number as the question. You find these buttons at the end of the test. You can also refresh your memory first by jumping directly to the answer buttons and click on them to get answers and read relevant parts of the book before doing this test.
On the questions with one or more possible answers (squares to click on) only the first click on each button is recorded as an answer. Hence you must click on the reset button below the question before you can change the original answer(s). Failure to do this will probably make the answers on this question regarded as wrong in the grading process.
Please observe that your teacher may require a deeper understanding of the treated subject than reflected by this test. In case you have any valuable comments or questions regarding this self-test, explain them in an e-mail to: jol@nc.chalmers.se


Question # 1 (One or more answers) Which of the following elements constitute together already >99% of the observable mass in the universe?

    A) H
    B) He
    C) Li
    D) Be
    E) Ne

In case of an error in the answers above, please click on this button before making any corrections 

Question # 2 (One answer) Stars in our galaxy's plane, who produce their energy by fusion of hydrogen, all fall on or near a smooth curve in a HR-diagram. This curve is called the

    A) Red-shift Sequence
    B) Hydrogen Line
    C) Long Series
    D) Main Sequence
    E) Assembly Line

Question # 3 (One answer) The well known spectral lines of the elements are shifted towards longer wave lengths in the light from distant stars. This is called a

    A) red-shift
    B) spectral anomaly
    C) blue-shift
    D) black-body radiation effect
    E) gravitational contraction

Question # 4 (One answer) Hydrogen degenerates to a plasma during gravity driven contraction of a gas who's density exceeds a certain value. This limiting density is called the

    A) Ultima Thule
    B) nova criterion
    C) Chandrasekhar limit
    D) Quo Vadis value
    E) p-p border

Question # 5 (One answer) With the nuclear lifetime of a star one understands the

    A) time that passes before a neutron star can be formed
    B) mean life-time of deuterium atoms in the center of the star
    C) the time it takes until the star consists of iron only
    D) inverse of the speed with which energy is radiated from the star
    E) time until 10% of the initial hydrogen has been consumed

Question # 6 (One or more answers) The Standard Model for evolution of stars is founded on a combination of

    A) the "Big Bang" theory
    B) the cosmic archeology
    C) the Bethe-Wiezsäcker model of the sun
    D) the Hubble law
    E) the red-shift

In case of an error in the answers above, please click on this button before making any corrections 

Question # 7 (One answer) A diagram in which the absolute luminosity of a star is plotted against its surface temperature is called a

    A) Luminosity plot
    B) Hertzsprung-Russell diagram
    C) Magnitude diagram
    D) Hubble diagram
    E) Red-shift curve

Question # 8 (One answer) One of the strongest supports for the "Big Bang" theory is that it predicted the existence of

    A) a red-shift
    B) a cosmic background radiation
    C) a cosmological constant
    D) clusters of galaxies
    E) Olber's paradox

Question # 9 (One answer) The assumption that the universe is isotropic on a large scale is called

    A) the Marvel of celestial mechanics
    B) the Cosmological principle
    C) the Harmony of the spheres
    D) Einstein principle
    E) Hubble principle

Question # 10 (One or more answers) One parsec is

    A) 3.1x1013 km
    B) 4.6x1017 m
    C) 0.332 light years
    D) 3.26 light years
    E) 10 light years

In case of an error in the answers above, please click on this button before making any corrections 

Question # 11 (One answer) How large fraction of hydrogen in the central parts of the Sun is now assumed to have been used up?

    A) about 1%
    B) about 9%
    C) about 17%
    D) about 52%
    E) about 98%

Question # 12 (One answer) The reason why the Sun now only produces about 10% of its energy via the CNO-cycle is that

    A) it lacks a sufficient number of carbon atoms
    B) it has too few nitrogen atoms in the corona
    C) its mass is too small
    D) it is not old enough
    E) the C and O atoms have formed CO2

Question # 13 (One answer) Observations of the variation of rotation speed with distance from the center made on many galaxies indicate that more than 90% of the mass in the universe is

    A) present in the galaxies
    B) interstellar gas
    C) in black holes near the center of the galaxies
    D) dark matter
    E) gone

Question # 14 (One or more answers) The Sun produces most of its energy through fusion reactions which belong to the

    A) 3a-process
    B) CNO-cycle
    C) uranium cycle
    D) proton-proton chain
    E) annihilation group

In case of an error in the answers above, please click on this button before making any corrections 

Question # 15 (One answer) How big is the difference in total reaction energy per produced He between a proton-proton chain and a CNO-cycle?

    A) 0 MeV
    B) 0.173 MeV
    C) 4.217 MeV
    D) 11.33 MeV
    E) 26.7 MeV

Question # 16 (One answer) By absolute luminosity is meant

    A) a relative scale for the total light emission from stars
    B) the magnitude of a star
    C) the light-flux from a star that is observed on Earth
    D) the total energy emitted by a star
    E) the strongest star that can be seen with the naked eye

Question # 17 (One or more answers) One or more of the following are known values for the solutions to the differential equations which describe the inner working and structure of a star: They are the

    A) total mass
    B) surface temperature
    C) absolute luminosity
    D) chemical composition at the surface
    E) age of the star

In case of an error in the answers above, please click on this button before making any corrections 

Question # 18 (One answer) The age of the universe can be estimated from a measurement of the

    A) constant of gravity
    B) cosmological constant
    C) velocity of light
    D) Hubble constant
    E) Fraunhofer lines

Question # 19 (One answer) The next stage in the development of the Sun is probably that it becomes a

    A) nova
    B) brown dwarf
    C) white dwarf
    D) blue-white giant
    E) red giant

Question # 20 (One answer) Why do we believe that initially there was more protons than neutrons?

    A) The neutron has always had a smaller cross section than the proton
    B) Free neutrons b-decay to protons
    C) The mass of the neutron is larger than the mass of the proton
    D) The photon energy was so high that the neutrons dissociated
    E) The gravitational force could not prevent the neutrons from leaving

Correct answers to each question can be obtained by clicking on the corresponding button below

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(Updated 2001-08-24)