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PPT – Approximately how many radioactive atoms are present in a tritium sample with an activity of 0'4 x 1 PowerPoint presentation | free to view - id: 15ef0b-YjBjY

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Approximately how many radioactive atoms are

present in a tritium sample with an activity of

0.4 x 10-6 Ci and a half-life of 12.3 years? (1

Ci 3.7 x 1010 decays/s)

- 13 x 107
- 7 x 108
- 3 x 1010
- 8 x 1012

What is the binding energy per nucleon of Au-197

(atomic number 79)? (The following information

regarding atomic masses will be needed Au-197,

196.966560 hydrogen, 1.007825 neutron,

1.008665 also 1 u x c2 931.5 MeV)

- 7.3 MeV
- 7.7 MeV
- 7.9 MeV
- 8.3 MeV

Approximately how many half-life periods must

elapse if the activity of a radioactive isotope

sample is to be reduced to 0.004 of the original

value?

- 3
- 6
- 8
- 60

Tritium has a half-life of 12.3 years. What

proportion of its original radioactivity will a

sample have after 9 years?

- 0.55
- 0.60
- 0.73
- 0.84

The activity of a newly discovered radioactive

isotope reduces to 96 of its original value in

an interval of 2 hours. What is its half-life?

- 10.2 hrs
- 34.0 hrs
- 44.0 hrs
- 68.6 hrs

If there are 128 neutrons in Pb-210, how many

neutrons are found in the nucleus of Pb-206?

- 122
- 124
- 126
- 130

The existence of the neutrino was postulated to

account for which basic conservation laws during

the beta decay process?

- conservation of energy
- conservation of momentum
- both of the choices are valid
- none of the choices are valid

A radioactive isotope which emits a gamma quantum

will change in what respect?

- atomic number increases by one
- atomic number decreases by one
- atomic mass number decreases by one
- none of the choices are valid

A radioactive isotope which emits an alpha

particle will change in what respect?

- atomic number decreases by four
- mass number decreases by four
- both atomic number and mass number decrease by

four - none of the choices are valid

Tritium has a half-life of 12.3 years. How many

years will elapse when the radioactivity of a

tritium sample diminishes to 10 of its original

value?

- 31 years
- 41 years
- 84 years
- 123 years

A pure sample of Ra-226 contains 2.0 x 1014 atoms

of the isotope. If the half-life of Ra-226 1.6

x 103 years, what is the decay rate of this

sample? (1 Ci 3.7 x 1010 decays/s)

- 2.7 x 10-12 Ci
- 3.4 x 10-10 Ci
- 7.5 x 10-8 Ci
- 9.6 x 10-6 Ci

What energy must be added or given off in a

reaction where one hydrogen atom and two neutrons

are combined to form a tritium atom? (atomic

masses for each hydrogen, 1.007825 neutron,

1.009665 tritium, 3.016049 also, 1 u x c2

931.5 MeV)

- 8.5 MeV added
- 8.5 MeV given off
- 10.3 MeV given off
- 10.3 MeV added

An ancient building was known to have been built

3000 years ago. Approximately what proportion of

C-14 atoms are yet in the building's wooden

framing compared to the number which were present

at the time of its construction? (half life of

C-14 5800 years)

- 0.425
- 0.500
- 0.517
- 0.698

The isotope Zn-64 has a nuclear radius of 4.8 x

10-15 m. Which of the following is the mass

number of an isotope for which the nuclear radius

is 7.2 x 10-15 m?

- 144
- 96
- 125
- 216

A pure sample of Ra-226 contains 2 x 1014 atoms

of the isotope. If the half-life of Ra-226 1.6

x 103 years, what is the decay rate of this

sample?

- 6.7 x 109 decays/yr
- 8.7 x 1010 decays/yr
- 9.4 x 1010 decays/yr
- 12.6 x 10-10 decays/yr

The beta emission process results in the daughter

nucleus differing in what manner from the parent?

- atomic mass increases by one
- atomic number decreases by two
- atomic number increases by one
- atomic mass decreases by two

The gamma radiation first detected by Becquerel

was in fact which of the following?

- helium nuclei
- high energy quanta
- electrons
- positrons

The alpha emission process results in the

daughter nucleus differing in what manner from

the parent?

- atomic mass increases by one
- atomic number decreases by two
- atomic number increases by one
- atomic mass decreases by two

If the sum total mass of reactants in a nuclear

reaction is greater than that of product

particles, then which of the following statements

best describes the conditions of the reaction?

- reaction is exothermic
- reaction is endothermic
- atomic number of each reactant must be greater

than 40 - atomic number of each reactant must be less than

80

The isotope Zn-64 has a nuclear radius of 4.8 x

10-15 m. Approximately what is the nuclear radius

of an isotope of Al-27?

- 2.0 x 10-15 m
- 2.7 x 10-15 m
- 3.6 x 10-15 m
- 4.0 x 10-15 m

The ratio of the numbers of neutrons to protons

in the nucleus of naturally occurring isotopes

tends to vary with atomic number in what manner?

- increases with greater atomic number
- decreases with greater atomic number
- is maximum for atomic number 60
- remains constant for entire range of atomic

numbers

The atomic mass number of a nucleus is equivalent

to which of the following numbers?

- neutrons present
- protons present
- difference in neutron and proton numbers
- sum of neutron and proton numbers

Of the main types of radiation emitted from

naturally radioactive isotopes, which of the

following is the most penetrating?

- alpha
- beta
- gamma
- positron

Samples of two different isotopes, X and Y, both

contain the same number of radioactive atoms.

Sample X has a half life twice that of Y. How do

their rates of radiation compare?

- X has a greater rate than Y
- X has a smaller rate than Y
- rates of X and Y are equal
- rate depends on atomic number, not half life

The beta radiation first detected by Becquerel

was in fact which of the following?

- helium nuclei
- high energy quanta
- electrons
- positrons

The alpha radiation first detected by Becquerel

was in fact which of the following?

- helium nuclei
- high energy quanta
- electrons
- positrons

The atomic number of a given element is

equivalent to which of the following?

- proton number in the nucleus
- neutron number in the nucleus
- sum of the protons and neutrons in the nucleus
- number of electrons in the outer shells

Chromium-55 (54.9279 u) emits an electron (0.0005

u) leaving a daughter nucleus of manganese-55

(54.9244 u). How much energy is released in this

reaction? (1 u x c2 931 MeV)

- 5.59 MeV
- 2.79 MeV
- 1.40 MeV
- 0.70 MeV

An endothermic nuclear reaction occurs as a

result of the collision of two reactant nuclei.

If the Q value of this reaction is -2.17 MeV,

which of the following describes the minimum

kinetic energy needed in the reactant nuclei if

the reaction is to occur?

- equal to 2.17 MeV
- greater than 2.17 MeV
- less than 2.17 MeV
- exactly half of 2.17 MeV

If a fossil bone is found to contain 1/8th as

much Carbon-14 as the bone of a living animal,

what is the approximate age of the fossil?

(half-life of C-14 5800 years)

- 8,000 years
- 17,400 years
- 23,000 years
- 46,400 years

Rutherford's experiments involving the use of

alpha particle beams directed onto thin metal

foils demonstrated the existence of which of the

following?

- neutron
- proton
- nucleus
- positron

The components of natural radiation, in order of

least to most penetrating, are which of the

following choices?

- alpha, beta and gamma
- gamma, beta and alpha
- beta, gamma and alpha
- alpha, gamma and beta

A radioactive material initially is observed to

have an activity of 800 counts/sec. If four hours

later it is observed to have an activity of 200

counts/sec, what is its half life?

- 1 hour
- 2 hours
- 4 hours
- 8 hours

The experiment which gave the first evidence for

the existence of the atomic nucleus involved

which of the following?

- X-ray scattering
- radioactive dating
- cosmic ray detection
- alpha scattering

The nucleus of an atom is made up of which of the

following?

- electrons and protons
- electrons and neutrons
- protons, electrons and neutrons
- protons and neutrons

Radium-226 decays to Radon-222 by emitting which

of the following?

- beta
- alpha
- gamma
- positron

When bismuth-214 emits a beta particle, the

remaining daughter nucleus is which of the

following?

- lead-213
- actinium-215
- polonium-214
- bismuth-215

Certain stars at the end of their lives are

thought to collapse combining their protons and

electrons together to form a neutron star. Such a

star could be thought of as a giant atomic

nucleus. If a star of mass equal to that of the

sun (M 2 x 1030 kg) collapsed into neutrons (mn

1.67 x 10-27 kg), what would be the radius of

such a star? (HINT r r0A1/3)

- 25.4 km
- 18.7 km
- 12.7 km
- 6.4 km

Calculate the binding energy of the tritium

nucleus, given that the mass of the tritium

nucleus is 3.01605 u. (mp 1.007276 u, mn

1.008665, and 1 u 931.5 MeV/c2)

- 2.24 MeV/nucleon
- 2.45 MeV/nucleon
- 2.66 MeV/nucleon
- 2.86 MeV/nucleon

The half-life of radioactive iodine-131 is 8

days. Find the number of 131I nuclei necessary to

produce a sample of activity 1.0µ Ci. (1 Curie

3.7 x 1010 decays/second)

- 4.6 x 109
- 3.7 x 1010
- 7.6 x 1012
- 8.1 x 1013

How much kinetic energy must an alpha particle

(charge 2 x 1.6 x 10-19 C) have to approach to

within 10-14 m of a gold nucleus (charge 79 x

1.6 x 10-19 C)? k 9 x 109 N-m2 /C2 and 1 MeV

1.6 x 10-13 J

- 11.70 MeV
- 14.55 MeV
- 18.15 MeV
- 22.75 MeV

Tritium is radioactive with a half-life of 12.33

years decaying into with low-energy

electron emission. If we have a sample of 3 x

1018 tritium atoms, what is its activity in

decays/second? (1 year 3.15 x 107 s)

- 4.20 x 1010/second
- 5.35 x 109/second
- 3.69 x 108/second
- 6.64 x 107/second

An alpha particle (mass 6.68 x 10-27 kg) is

emitted from a radioactive nucleus with an energy

of 5 MeV. How fast is the a-particle moving in

m/s? (1 MeV 1.6 x 10-13 J)

- 2.40 x 107 m/s
- 1.55 x 107 m/s
- 3.70 x 106 m/s
- 1.85 x 106 m/s

A 1-gram sample of petrified wood is taken from a

petrified forest. If the Carbon-14 activity of

the sample is 12.5 that of present-day organic

material, what is the age of the petrified wood?

(T1/2 for C-14 is 5,730 years)

- 4,460 years
- 8,600 years
- 13,150 years
- 17,200 years

In the beta decay of 14C, the existence of the

anti-neutrino was required to maintain?

- energy conservation.
- charge conservation.
- conservation of the number of nucleons.
- all of the choices

The fact that the binding energy per nucleon

doesn't depend very strongly on the volume of the

nucleus indicates that?

- the strong nuclear force saturates.
- nucleons don't move throughout the nucleus.
- all nuclei have the same volume.
- the radius of a nucleus is directly proportional

to the number of nucleons.

According to the shell model of the nucleus,

radioactive decay which produces beta rays occurs

because?

- there is a vacant energy level for a neutron and

as a neutron drops down to this lower energy

level it gives up its energy to an electron. - there is no vacancy in a neutron energy level so

the neutron goes to an energy level previously

occupied by an electron. - the neutron must change to a proton before it can

go to a lower energy level. - the neutron gets rid of excess angular momentum

by giving it to ejected electron.

Some nuclei are not spherical and this can best

be explained by the?

- liquid drop model.
- shell model.
- collective model.
- model of nuclear tunneling.

If the stable nuclei are plotted with neutron

number vs. proton number, the curve formed by the

stable nuclei does not follow the line N Z.

This is predicted by examining how the binding

energy is influenced by?

- the volume of the nucleus.
- the size of the nuclear surface.
- the Coulomb repulsion.
- the proton-neutron mass difference.

The binding energy of a nucleus is equal to?

- the energy needed to remove one of the nucleons.
- the average energy with which any nucleon is

bound in the nucleus. - the energy needed to separate all the nucleons

from each other. - the mass of the nucleus times c2.

The gram molecular mass for chlorine is not a

multiple of the mass of hydrogen but is about

35.5 times the mass of hydrogen. This is

primarily because?

- the proton and neutron have different masses.
- there are several isotopes of chlorine.
- of the binding energy of the chlorine nucleus.
- the chlorine nucleus has 35.5 nucleons.

The mass of 238U is not quite an integer multiple

of -H. This is primarily because?

- the proton and neutron have different masses.
- there are several isotopes of uranium.
- of the binding energy of uranium.
- uranium is radioactive.

The neutron is radioactive and can beta decay to

form a proton. This can occur primarily because?

- the proton has less mass than a neutron.
- there are several hydrogen isotopes.
- of the binding energy of hydrogen.
- the neutron is neutral.

For every stable nucleus except hydrogen, if the

number of nucleons is doubled, the quantity that

will change least is the?

- mass.
- charge.
- volume.
- density.

What particle is emitted when P-32 decays to

S-32? (atomic numbers of P and S are,

respectively, 15 and 16)

- alpha
- beta
- positron
- gamma quantum

What particle is emitted when Pu-240 decays to

U-236? (atomic numbers of Pu and U are,

respectively, 94 and 92)

- alpha
- beta
- positron
- gamma quantum

The original nucleus and the final nucleus will

be isotopes for which decay scheme of the

original nucleus?

- alpha decay followed by two beta decays
- two gamma decays
- a beta decay followed by an alpha decay
- a beta decay followed by neutron emission

The mass of 12C is 12 u where 1 u 1.660559 x

10-27 kg. This mass is equal to?

- the mass of the 12C nucleus.
- the mass of the 12C nucleus plus 6 electrons.
- the mass of the 12C nucleus plus 12 electrons.
- the mass of 6 protons and 6 neutrons.

A proton is captured by an oxygen-16 atom which

in turn emits a deuteron. What is the element and

mass number of the product isotope?

- nitrogen-15
- oxygen-17
- oxygen-15
- fluorine-15