Question 1

What would be the expected radius of the nucleus of   Sr?

Accepted Answer

A)  4.0 fm 
B)  1.2 fm 
C)  5.4 fm 
D)  0.11 pm 
E)  0.54 pm 
A)  4.0 fm 
B)  1.2 fm 
C)  5.4 fm 
D)  0.11 pm 
E)  0.54 pm

Question 2

For the missing product X in the nuclear reaction
neutron +   O → X + alpha particle
determine the atomic mass and atomic number of X,and write X in the standard form.It is NOT necessary to identify which atom X is.

Accepted Answer

The answer of For the missing product X in the...

Question 3

In the nuclear reaction
n +   U → X + 2e-
n is a neutron and e- is an electron,and the neutrinos have not been shown.Determine the atomic mass and atomic number of the missing nuclear product X,and write X in the standard form.It is NOT necessary to identify which atom X is.

Accepted Answer

Question 4

The detonation of a certain nuclear device results in a mass decrease of   between the initial and the final ingredients.How much energy is released by this detonation?

Accepted Answer

A)  2.34 × 1014 J 
B)  7.80 × 105 J 
C)  2.34 × 1013 J 
D)  2.78 × 1012 J 
A)  2.34 × 1014 J 
B)  7.80 × 105 J 
C)  2.34 × 1013 J 
D)  2.78 × 1012 J

Question 5

A radioactive sample has a half-life of 10 min.What fraction of the sample is left after 40 min?

Accepted Answer

A)  1/2 
B)  1/4 
C)  1/8 
D)  1/16 
E)  1/32 
A)  1/2 
B)  1/4 
C)  1/8 
D)  1/16 
E)  1/32

Question 6

An ancient rock is found to contain 40Ar gas,indicating that   of the 40K in the rock has decayed since the rock solidified.Any argon would have boiled out of liquid rock.The half-life of 40K is 1.25 billion years.How long ago did the rock solidify?

Accepted Answer

A)  2.6 billion years 
B)  0.50 billion years 
C)  1.8 billion years 
D)  0.30 billion years 
A)  2.6 billion years 
B)  0.50 billion years 
C)  1.8 billion years 
D)  0.30 billion years

Question 7

Living matter has 1.3 × 10-10 % of its carbon in the form of 14C which has a half-life of 5730 y.A mammoth bone has a 300-g sample of carbon separated from it,and the sample is found to have an activity of 20 decays per second.How old is the bone?

Accepted Answer

A)  15,000 y 
B)  10,900 y 
C)  11,500 y 
D)  7600 y 
E)  6400 y 
A)  15,000 y 
B)  10,900 y 
C)  11,500 y 
D)  7600 y 
E)  6400 y

Question 8

If a 2.0-MeV neutron released in a fission reaction loses half of its energy in each moderator collision,how many collisions are needed to reduce its energy to (1/25)eV?

Accepted Answer

A)  6 
B)  18 
C)  26 
D)  30 
E)  4 
A)  6 
B)  18 
C)  26 
D)  30 
E)  4

Question 9

A certain nucleus containing 8 protons and 7 neutrons has a radius R.Which of the following values would be closest to the expected value of the radius of a nucleus having 51 protons and 69 neutrons?

Accepted Answer

A)  1.85R 
B)  2.00R 
C)  2.14R 
D)  6.38R 
E)  8.00R 
A)  1.85R 
B)  2.00R 
C)  2.14R 
D)  6.38R 
E)  8.00R

Question 10

An isotope of Tc having a half-life of 6.0 h is used in bone scans.If a certain amount of this Tc is injected into the body,how long does it take for its initial decay rate to decrease BY 99%?

Accepted Answer

A)  0.060 h 
B)  3.3 h 
C)  33 h 
D)  40 h 
E)  slightly more than a month 
A)  0.060 h 
B)  3.3 h 
C)  33 h 
D)  40 h 
E)  slightly more than a month

Question 11

What would be the expected radius of a nucleus having 82 protons and 125 neutrons?

Accepted Answer

A)  5.2 fm 
B)  5.9 fm 
C)  6.0 fm 
D)  7.1 fm 
E)  17 fm 
A)  5.2 fm 
B)  5.9 fm 
C)  6.0 fm 
D)  7.1 fm 
E)  17 fm

Question 12

Carbon-14 has a half-life of 5730 y.A sample of wood has been recovered by an archaeologist.The sample is sent to a laboratory,where it is determined that the activity of the sample is 0.144 Bq/g.By comparing this activity with the activity of living organic matter,0.230 Bq/g,the scientist determines how old the wood sample is,or more precisely,when the tree that the sample came from died.How old is the sample of wood?

Accepted Answer

A)  3870 y 
B)  4250 y 
C)  4590 y 
D)  2630 y 
E)  2940 y 
A)  3870 y 
B)  4250 y 
C)  4590 y 
D)  2630 y 
E)  2940 y

Question 13

If a nucleus decays by alpha decay to a daughter nucleus,which of the following statements about this decay are correct? (There may be more than one correct choice.)

Accepted Answer

A)  The daughter nucleus has more protons than the original nucleus. 
B)  The daughter nucleus has more neutrons than the original nucleus. 
C)  The daughter nucleus has the same number of nucleons as the original nucleus. 
D)  The daughter nucleus has fewer protons than the original nucleus. 
E)  The daughter nucleus has fewer neutrons than the original nucleus. 
A)  The daughter nucleus has more protons than the original nucleus. 
B)  The daughter nucleus has more neutrons than the original nucleus. 
C)  The daughter nucleus has the same number of nucleons as the original nucleus. 
D)  The daughter nucleus has fewer protons than the original nucleus. 
E)  The daughter nucleus has fewer neutrons than the original nucleus.

Question 14

Scandium,   Sc,decays by emitting a positron.What is the nuclide that is the product of the decay?

Accepted Answer

A)    Sc 
B)    Sc 
C)    Ca 
D)    Ca 
E)    Sc 
A)    Sc 
B)    Sc 
C)    Ca 
D)    Ca 
E)    Sc

Question 15

A proton strikes an   O nucleus producing   F and another particle.What is the other particle?

Accepted Answer

A)  a neutron 
B)  an alpha particle 
C)  a β- particle 
D)  a β+ particle 
E)  a gamma ray 
A)  a neutron 
B)  an alpha particle 
C)  a β- particle 
D)  a β+ particle 
E)  a gamma ray

Question 16

The reaction energy (Q value)for a particular reaction is -2.4 MeV,and the reaction's threshold energy is 9.60 MeV.What is the ratio of the mass of the incident particle to the mass of the stationary target nucleus?

Accepted Answer

A)  0.75 
B)  0.25 
C)  3.0 
D)  4.0 
E)  5.0 
A)  0.75 
B)  0.25 
C)  3.0 
D)  4.0 
E)  5.0

Question 17

Find the reaction energy (Q value)of the reaction   N +   He →   O +   H,given the following masses:   N: 14.003074 u   He: 4.002603 u   O : 16.999131 u   H: 1.007825 u (1 u = 931.5 MeV/c2)

Accepted Answer

A)  -1.191 MeV 
B)  -2.030 MeV 
C)  -3.241 MeV 
D)  -6.724 MeV 
E)  -9.055 MeV 
A)  -1.191 MeV 
B)  -2.030 MeV 
C)  -3.241 MeV 
D)  -6.724 MeV 
E)  -9.055 MeV

Question 18

The unstable isotope 234Th decays by β emission with a half-life of 24.5 days.The initial decay rate of the sample was 9.9 × 1013 Bq.(1 u = 1.6605 × 10-27 kg)
(a)What mass of 234Th was initially present?
(b)What is the decay rate after 68 days?

Accepted Answer

(a)0.12 g

Question 19

The stability of   C with respect to alpha,β+,and β- decay is to be determined.Do not consider the possibility of decay by electron capture.The following atomic masses are known:   He: 4.002603 u   Be: 7.016928 u   B: 11.009305 u   C: 11.011433 u   N: 11.026742 u The   C nuclide is

Accepted Answer

A)  not subject to alpha, β+, or β- decay. 
B)  subject to alpha decay only. 
C)  subject to β+ decay only. 
D)  subject to β- decay only. 
E)  subject to β+ or β- decay, but not to alpha decay. 
A)  not subject to alpha, β+, or β- decay. 
B)  subject to alpha decay only. 
C)  subject to β+ decay only. 
D)  subject to β- decay only. 
E)  subject to β+ or β- decay, but not to alpha decay.

Question 20

How many days are required for a radioactive sample,with a half-life of 5.7 d and an initial activity of 1.07 × 105 Bq,to decay to an activity of 100 Bq?

Accepted Answer

A)  57 d 
B)  46 d 
C)  68 d 
D)  39 d 
A)  57 d 
B)  46 d 
C)  68 d 
D)  39 d

Exam 43: Nuclear Physics

What would be the expected radius of the nucleus of Sr?

For the missing product X in the nuclear reaction neutron + O → X + alpha particle determine the atomic mass and atomic number of X,and write X in the standard form.It is NOT necessary to identify which atom X is.

In the nuclear reaction n + U → X + 2e- n is a neutron and e- is an electron,and the neutrinos have not been shown.Determine the atomic mass and atomic number of the missing nuclear product X,and write X in the standard form.It is NOT necessary to identify which atom X is.

The detonation of a certain nuclear device results in a mass decrease of between the initial and the final ingredients.How much energy is released by this detonation?

A radioactive sample has a half-life of 10 min.What fraction of the sample is left after 40 min?

An ancient rock is found to contain 40Ar gas,indicating that of the 40K in the rock has decayed since the rock solidified.Any argon would have boiled out of liquid rock.The half-life of 40K is 1.25 billion years.How long ago did the rock solidify?

Living matter has 1.3 × 10-10 % of its carbon in the form of 14C which has a half-life of 5730 y.A mammoth bone has a 300-g sample of carbon separated from it,and the sample is found to have an activity of 20 decays per second.How old is the bone?

If a 2.0-MeV neutron released in a fission reaction loses half of its energy in each moderator collision,how many collisions are needed to reduce its energy to (1/25)eV?

A certain nucleus containing 8 protons and 7 neutrons has a radius R.Which of the following values would be closest to the expected value of the radius of a nucleus having 51 protons and 69 neutrons?

An isotope of Tc having a half-life of 6.0 h is used in bone scans.If a certain amount of this Tc is injected into the body,how long does it take for its initial decay rate to decrease BY 99%?

What would be the expected radius of a nucleus having 82 protons and 125 neutrons?

If a nucleus decays by alpha decay to a daughter nucleus,which of the following statements about this decay are correct? (There may be more than one correct choice.)

Scandium, Sc,decays by emitting a positron.What is the nuclide that is the product of the decay?

A proton strikes an O nucleus producing F and another particle.What is the other particle?

The reaction energy (Q value)for a particular reaction is -2.4 MeV,and the reaction's threshold energy is 9.60 MeV.What is the ratio of the mass of the incident particle to the mass of the stationary target nucleus?

Find the reaction energy (Q value)of the reaction N + He → O + H,given the following masses: N: 14.003074 u He: 4.002603 u O : 16.999131 u H: 1.007825 u (1 u = 931.5 MeV/c2)

The unstable isotope 234Th decays by β emission with a half-life of 24.5 days.The initial decay rate of the sample was 9.9 × 1013 Bq.(1 u = 1.6605 × 10-27 kg) (a)What mass of 234Th was initially present? (b)What is the decay rate after 68 days?

The stability of C with respect to alpha,β+,and β- decay is to be determined.Do not consider the possibility of decay by electron capture.The following atomic masses are known: He: 4.002603 u Be: 7.016928 u B: 11.009305 u C: 11.011433 u N: 11.026742 u The C nuclide is

How many days are required for a radioactive sample,with a half-life of 5.7 d and an initial activity of 1.07 × 105 Bq,to decay to an activity of 100 Bq?

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Filters

In the nuclear reaction n + U → X + 2e^- n is a neutron and e^- is an electron,and the neutrinos have not been shown.Determine the atomic mass and atomic number of the missing nuclear product X,and write X in the standard form.It is NOT necessary to identify which atom X is.

An ancient rock is found to contain ⁴⁰Ar gas,indicating that of the ⁴⁰K in the rock has decayed since the rock solidified.Any argon would have boiled out of liquid rock.The half-life of ⁴⁰K is 1.25 billion years.How long ago did the rock solidify?

Living matter has 1.3 × 10^-10 % of its carbon in the form of ¹⁴C which has a half-life of 5730 y.A mammoth bone has a 300-g sample of carbon separated from it,and the sample is found to have an activity of 20 decays per second.How old is the bone?

_{An isotope of Tc having a half-life of 6.0 h is used in bone scans.If a certain amo}_{unt of this Tc is injected into the body,how long does it take for its initial decay rate to decrease BY 99%?}

Find the reaction energy (Q value)of the reaction N + He → O + H,given the following masses: N: 14.003074 u He: 4.002603 u O : 16.999131 u H: 1.007825 u (1 u = 931.5 MeV/c²)

The unstable isotope ²³⁴Th decays by β emission with a half-life of 24.5 days.The initial decay rate of the sample was 9.9 × 10¹³ Bq.(1 u = 1.6605 × 10^-27 kg) (a)What mass of ²³⁴Th was initially present? (b)What is the decay rate after 68 days?

The stability of C with respect to alpha,β⁺,and β^-decay is to be determined.Do not consider the possibility of decay by electron capture.The following atomic masses are known: He: 4.002603 u Be: 7.016928 u B: 11.009305 u C: 11.011433 u N: 11.026742 u The C nuclide is

How many days are required for a radioactive sample,with a half-life of 5.7 d and an initial activity of 1.07 × 10⁵ Bq,to decay to an activity of 100 Bq?