Question 1

If you begin with a sample of 2.50 moles of a radioactive isotope and there are 2.05 * 1021 atoms left after one hour,what is the mean lifetime of this isotope?

Accepted Answer

A) 8.4 minutes 
B) 7.5 minutes 
C) 6.3 minutes 
D) 9.1 minutes 
A) 8.4 minutes 
B) 7.5 minutes 
C) 6.3 minutes 
D) 9.1 minutes

Question 2

A drug containing   (   = 6.05 h)is to be injected into a patient at 10:00 am.You are to prepare the sample 3.00 hours before the injection (at 7:00 am)with an activity of 3.53 $\mu$Ci at the preparation time (7:00 am).What will be the activity of the sample at the time of the injection?

Accepted Answer

A) 1.50 $\mu$Ci 
B) 2.00 $\mu$Ci 
C) 2.50 $\mu$Ci 
D) 3.00 $\mu$Ci 
E) 3.50 $\mu$Ci 
A) 1.50 $\mu$Ci 
B) 2.00 $\mu$Ci 
C) 2.50 $\mu$Ci 
D) 3.00 $\mu$Ci 
E) 3.50 $\mu$Ci

Question 3

A nuclear fission power plant produces about 2.00 GW of electrical power.Assume that that each fission produces 200.0 MeV of energy and that the mass of 235U consumed each day is 5.50 kg.The overall efficiency of the plant is

Accepted Answer

A) 32.4%. 
B) 38.3%. 
C) 41.5%. 
D) 46.2%. 
E) 51.7%. 
A) 32.4%. 
B) 38.3%. 
C) 41.5%. 
D) 46.2%. 
E) 51.7%.

Question 4

What is the binding energy per nucleon of 56Fe? The atomic mass of 56Fe is 55.9349 u,the mass of a proton = 1.0078 u,the mass of a neutron = 1.0087 u,the atomic number Z = 26 and the atomic mass A = 56.

Accepted Answer

A) 9.01 MeV 
B) 8.79 MeV 
C) 7.95 MeV 
D) 7.22 MeV 
A) 9.01 MeV 
B) 8.79 MeV 
C) 7.95 MeV 
D) 7.22 MeV

Question 5

In neutron stars,which are roughly 90% neutrons and supported almost entirely by nuclear forces,which of the following binding energy terms becomes relatively dominant compared to ordinary nuclei?

Accepted Answer

A) the coulomb term 
B) the asymmetry term 
C) the pairing term 
D) All are correct. 
E) None are correct. 
A) the coulomb term 
B) the asymmetry term 
C) the pairing term 
D) All are correct. 
E) None are correct.

Question 6

An archeologist discovers the bones of a person believed to have been dead for 600 years.Using carbon dating,they wish to confirm the time of the person's demise.The rate of change of   is 0.270 Bq/g of carbon for the bones of a person who had just died.If the archeologist is correct about the person's time of death,what rate of change of   should they find when they carbon date the bones? The half life of   is 5.73 x 103 y.

Accepted Answer

A) 0.245 Bq/g 
B) 0.267 Bq/g 
C) 0.251 Bq/g 
D) 0.238 Bq/g 
E) 0.259 Bq/g 
A) 0.245 Bq/g 
B) 0.267 Bq/g 
C) 0.251 Bq/g 
D) 0.238 Bq/g 
E) 0.259 Bq/g

Question 7

Sirius,the brightest star in the night sky coverts 3.216 * 1018 kg of its mass to energy every year.What is the luminosity (power radiated)of Sirius?

Accepted Answer

A) 3.91 * 1026 W 
B) 1.09 * 1027 W 
C) 1.33 * 1028 W 
D) 5.23 * 1027 W 
E) 9.18 * 1027 W 
A) 3.91 * 1026 W 
B) 1.09 * 1027 W 
C) 1.33 * 1028 W 
D) 5.23 * 1027 W 
E) 9.18 * 1027 W

Question 8

If you begin with a sample of 2.50 moles of a radioactive isotope and there are 2.05 * 1021 atoms left after one hour,what is the half-life of this isotope?

Accepted Answer

A) 9.1 minutes 
B) 6.3 minutes 
C) 13 minutes 
D) 7.5 minutes 
A) 9.1 minutes 
B) 6.3 minutes 
C) 13 minutes 
D) 7.5 minutes

Question 9

If Carbon-14,a beta emitter with a half-life of 5730 years,makes up one out of 1012 Carbon atoms in nature,how many decays per second are there in a 15 kg bag of charcoal (taken to be 100% carbon)?

Accepted Answer

A) 1720 
B) 2010 
C) 2480 
D) 2890 
E) None are correct. 
A) 1720 
B) 2010 
C) 2480 
D) 2890 
E) None are correct.

Question 10

A nuclear fission power plant produces about 2.50 GW of electrical power.Assume that the plant has an overall efficiency of 40.0% and that each fission produces 200.0 MeV of energy.Calculate the number of 235U fissions required each day.

Accepted Answer

A) 6.75 * 1024 
B) 3.12 * 1025 
C) 2.41 * 1025 
D) 2.89 * 1025 
E) 1.69 * 1025 
A) 6.75 * 1024 
B) 3.12 * 1025 
C) 2.41 * 1025 
D) 2.89 * 1025 
E) 1.69 * 1025

Question 11

A radioactive material has a half life of 20 seconds.If the initial amount of material is G grams,how much will be left at the end of one minute?

Accepted Answer

A) G/3 
B) G/4 
C) G/6 
D) G/8 
E) G/16 
A) G/3 
B) G/4 
C) G/6 
D) G/8 
E) G/16

Question 12

Which of the following would you expect to decay via b+ decay?

Accepted Answer

A) 12C 
B) 132Sn 
C) 56Fe 
D) 74Kr 
E) 17N 
A) 12C 
B) 132Sn 
C) 56Fe 
D) 74Kr 
E) 17N

Question 13

The volume of a nucleus is proportional to

Accepted Answer

A) the atomic number Z. 
B) the atomic mass number 
C) the neutron number N. 
D) the number of electrons. 
A) the atomic number Z. 
B) the atomic mass number 
C) the neutron number N. 
D) the number of electrons.

Question 14

A muon has a mean lifetime of only 2.200 µs in its own rest frame.If it moves with a speed of v = 0.9994 c in a certain reference frame,what is its mean lifetime in that frame?

Accepted Answer

A) 0.042 µs 
B) 2.2 µs 
C) 9.99 µs 
D) 63.5 µs 
E) 4200 µs 
A) 0.042 µs 
B) 2.2 µs 
C) 9.99 µs 
D) 63.5 µs 
E) 4200 µs

Question 15

131I,which has a half- life time of 8 days,is used in nuclear medicine to monitor the hormone production in the thyroid in a patient.A sample of 131I containing 5 * 1010 atoms is produced in a nuclear reactor.Due to the short half- life time,the sample emits less radiation with time.However,it is usable as long as there are at least 1.25 * 1010 131I atoms present.What is the maximum time before the sample is no longer usable?

Accepted Answer

A) 16 days 
B) 12 days 
C) 8 days 
D) 6 days 
A) 16 days 
B) 12 days 
C) 8 days 
D) 6 days

Question 16

A radioactive atom undergoes $\beta$- decay by emitting an electron and an anti-electron neutrino.When this occurs,what happens to the number of neutrons in the atom?

Accepted Answer

A) increases. 
B) decreases. 
C) remains constant. 
D) One can't determine what happens to the number of neutrons using only the information given. 
A) increases. 
B) decreases. 
C) remains constant. 
D) One can't determine what happens to the number of neutrons using only the information given.

Question 17

if the mass of a star changes at a rate of 8.7 * 1013 kg/day,at what rate does the star radiate energy?

Accepted Answer

A) 2.32 * 1026 W 
B) 3.85 * 1026 W 
C) 1.12 * 1026 W 
D) 8.12 * 1025 W 
E) 9.06 * 1025 W 
A) 2.32 * 1026 W 
B) 3.85 * 1026 W 
C) 1.12 * 1026 W 
D) 8.12 * 1025 W 
E) 9.06 * 1025 W

Question 18

When 21583Bi decays to 21584Po,what particle is released?

Accepted Answer

A) proton 
B) neutron 
C) positron 
D) electron 
E) alpha 
A) proton 
B) neutron 
C) positron 
D) electron 
E) alpha

Question 19

If the Fermi energy of a neutron inside a nucleus is 38 MeV,what is the Fermi momentum?

Accepted Answer

A) 38 MeV/c 
B) 270 MeV/c 
C) 370 MeV/c 
D) 154 MeV/c 
A) 38 MeV/c 
B) 270 MeV/c 
C) 370 MeV/c 
D) 154 MeV/c

Question 20

Assuming that a neutron star is as dense as an atomic nucleus,estimate the number of nucleons in a 10 km diameter star.

Accepted Answer

A) 3.2* 1053 
B) 4.5 * 1054 
C) 8.9*1055 
D) 7.1 * 1056 
E) 2.1 *1057 
A) 3.2* 1053 
B) 4.5 * 1054 
C) 8.9*1055 
D) 7.1 * 1056 
E) 2.1 *1057

Exam 40: Nuclear Physics

If you begin with a sample of 2.50 moles of a radioactive isotope and there are 2.05 * 1021 atoms left after one hour,what is the mean lifetime of this isotope?

A drug containing ( = 6.05 h)is to be injected into a patient at 10:00 am.You are to prepare the sample 3.00 hours before the injection (at 7:00 am)with an activity of 3.53 μ\muμ Ci at the preparation time (7:00 am).What will be the activity of the sample at the time of the injection?

A nuclear fission power plant produces about 2.00 GW of electrical power.Assume that that each fission produces 200.0 MeV of energy and that the mass of 235U consumed each day is 5.50 kg.The overall efficiency of the plant is

What is the binding energy per nucleon of 56Fe? The atomic mass of 56Fe is 55.9349 u,the mass of a proton = 1.0078 u,the mass of a neutron = 1.0087 u,the atomic number Z = 26 and the atomic mass A = 56.

In neutron stars,which are roughly 90% neutrons and supported almost entirely by nuclear forces,which of the following binding energy terms becomes relatively dominant compared to ordinary nuclei?

Sirius,the brightest star in the night sky coverts 3.216 * 1018 kg of its mass to energy every year.What is the luminosity (power radiated)of Sirius?

If you begin with a sample of 2.50 moles of a radioactive isotope and there are 2.05 * 1021 atoms left after one hour,what is the half-life of this isotope?

If Carbon-14,a beta emitter with a half-life of 5730 years,makes up one out of 1012 Carbon atoms in nature,how many decays per second are there in a 15 kg bag of charcoal (taken to be 100% carbon)?

A nuclear fission power plant produces about 2.50 GW of electrical power.Assume that the plant has an overall efficiency of 40.0% and that each fission produces 200.0 MeV of energy.Calculate the number of 235U fissions required each day.

A radioactive material has a half life of 20 seconds.If the initial amount of material is G grams,how much will be left at the end of one minute?

Which of the following would you expect to decay via b+ decay?

The volume of a nucleus is proportional to

A muon has a mean lifetime of only 2.200 µs in its own rest frame.If it moves with a speed of v = 0.9994 c in a certain reference frame,what is its mean lifetime in that frame?

A radioactive atom undergoes β\betaβ - decay by emitting an electron and an anti-electron neutrino.When this occurs,what happens to the number of neutrons in the atom?

if the mass of a star changes at a rate of 8.7 * 1013 kg/day,at what rate does the star radiate energy?

When 21583Bi decays to 21584Po,what particle is released?

If the Fermi energy of a neutron inside a nucleus is 38 MeV,what is the Fermi momentum?

Assuming that a neutron star is as dense as an atomic nucleus,estimate the number of nucleons in a 10 km diameter star.

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If you begin with a sample of 2.50 moles of a radioactive isotope and there are 2.05 * 10²¹ atoms left after one hour,what is the mean lifetime of this isotope?

A nuclear fission power plant produces about 2.00 GW of electrical power.Assume that that each fission produces 200.0 MeV of energy and that the mass of ²³⁵U consumed each day is 5.50 kg.The overall efficiency of the plant is

What is the binding energy per nucleon of ⁵⁶Fe? The atomic mass of ⁵⁶Fe is 55.9349 u,the mass of a proton = 1.0078 u,the mass of a neutron = 1.0087 u,the atomic number Z = 26 and the atomic mass A = 56.

Sirius,the brightest star in the night sky coverts 3.216 * 10¹⁸ kg of its mass to energy every year.What is the luminosity (power radiated)of Sirius?

If you begin with a sample of 2.50 moles of a radioactive isotope and there are 2.05 * 10²¹ atoms left after one hour,what is the half-life of this isotope?

If Carbon-14,a beta emitter with a half-life of 5730 years,makes up one out of 10¹² Carbon atoms in nature,how many decays per second are there in a 15 kg bag of charcoal (taken to be 100% carbon)?

A nuclear fission power plant produces about 2.50 GW of electrical power.Assume that the plant has an overall efficiency of 40.0% and that each fission produces 200.0 MeV of energy.Calculate the number of ²³⁵U fissions required each day.

Which of the following would you expect to decay via b⁺ decay?

A radioactive atom undergoes $\beta$ ^- decay by emitting an electron and an anti-electron neutrino.When this occurs,what happens to the number of neutrons in the atom?

if the mass of a star changes at a rate of 8.7 * 10¹³ kg/day,at what rate does the star radiate energy?

When ²¹⁵₈₃Bi decays to ²¹⁵₈₄Po,what particle is released?