Question 1

A certain radioactive isotope decays to one sixteenth of its original amount in 4.0 hours.What is its half-life?

Accepted Answer

A) 1.0 hours 
B) 2.5 hours 
C) 2.0 hours 
D) 1.4 hours 
A) 1.0 hours 
B) 2.5 hours 
C) 2.0 hours 
D) 1.4 hours A

Question 2

Which of the following is true about strong force?

Accepted Answer

A) is only attractive 
B) does not act on electrons 
C) only acts over a few fm 
D) All are correct. 
A) is only attractive 
B) does not act on electrons 
C) only acts over a few fm 
D) All are correct. D

Question 3

When 21083Bi decays its half life is 5.0 seconds.What is the activity in Bq (disintegrations per second)of one mole?

Accepted Answer

A) 6.02 * 1023/5 
B) 0.69 * 6.02 * 1023/5 
C) 5 * 6.02 * 1023 
D) 6.02 * 1023/5 * 0.69 
E) 5 * 6.02 * 1023/0.69 
A) 6.02 * 1023/5 
B) 0.69 * 6.02 * 1023/5 
C) 5 * 6.02 * 1023 
D) 6.02 * 1023/5 * 0.69 
E) 5 * 6.02 * 1023/0.69 B

Question 4

The half-life of Co-57 is 271.8 days;calculate the decay constant.

Accepted Answer

A) 11.2 * 10-8 s-1 
B) 16.0 * 10-4 s-1 
C) 2.95 * 108 s-1 
D) 3.0 * 10-8 s-1 
E) 6.3 * 106 s-1 
A) 11.2 * 10-8 s-1 
B) 16.0 * 10-4 s-1 
C) 2.95 * 108 s-1 
D) 3.0 * 10-8 s-1 
E) 6.3 * 106 s-1

Question 5

Assuming that a neutron star is as dense as an atomic nucleus,estimate the mass of a neutron star having a diameter of 10 km.

Accepted Answer

A) 1.5 * 1029 kg 
B) 1.1 * 1029 kg 
C) 3.2 * 1029 kg 
D) 2.1 * 1029 kg 
E) 1.8 * 1029 kg 
A) 1.5 * 1029 kg 
B) 1.1 * 1029 kg 
C) 3.2 * 1029 kg 
D) 2.1 * 1029 kg 
E) 1.8 * 1029 kg

Question 6

What is the surface area,approximately,of a Lead-208 nucleus (Z = 82)?

Accepted Answer

A) 550 fm2 
B) 140 fm2 
C) 440 fm2 
D) 74 fm2 
E) 120 fm2 
A) 550 fm2 
B) 140 fm2 
C) 440 fm2 
D) 74 fm2 
E) 120 fm2

Question 7

In 1991 a frozen body of an "Iceman" was found in the Italian Alps.The fraction of   compared to   found in the body's bones,hair,and leather clothing was 6.94 * 10-13.The half-life of   is 5,730 years and the ratio of   to   in living organisms is 1 to 7.41 *1011.When did the Iceman die?

Accepted Answer

A) 2500 years ago 
B) 3800 years ago 
C) 5500 years ago 
D) 7600 years ago 
E) 11,000 years ago 
A) 2500 years ago 
B) 3800 years ago 
C) 5500 years ago 
D) 7600 years ago 
E) 11,000 years ago

Question 8

Atoms consist of protons,neutrons,and electrons.Which determines an element of the periodic table?

Accepted Answer

A) the number of protons only 
B) the number of neutrons only 
C) the number of protons and neutrons 
D) the number of protons,neutrons,and electrons 
A) the number of protons only 
B) the number of neutrons only 
C) the number of protons and neutrons 
D) the number of protons,neutrons,and electrons

Question 9

A drug containing   with an activity of 2.00 $\mu$Ci is to be injected into a patient at 11:00 am.A sample is prepared 4.00 hours before the injection (at 7:00 am).The activity of the drug have at the preparation time (7:00 am)was 3.16 $\mu$Ci.What is the mean lifetime of   ?

Accepted Answer

A) 6.05 hr 
B) 8.74 hr 
C) 12.6 hr 
D) 7.45 hr 
E) 6.91 hr 
A) 6.05 hr 
B) 8.74 hr 
C) 12.6 hr 
D) 7.45 hr 
E) 6.91 hr

Question 10

A Geiger counter placed next to a radioactive sample produces 200 counts per minute.One hour later,the Geiger counter reads 180 counts per minute.What is the half-life of the radioactive sample?

Accepted Answer

A) 1.1 hours 
B) 6.6 hours 
C) 9.0 hours 
D) 9.5 hours 
E) 10 hours 
A) 1.1 hours 
B) 6.6 hours 
C) 9.0 hours 
D) 9.5 hours 
E) 10 hours

Question 11

A tree is chopped down and burned to produce ash.The carbon isotopes in the ash are found to have a ratio for 14C to 12C of 1.3 * 10-12.Experimental tests on the 14C atoms reveal that 14C is a beta emitter with a half-life of 5730 years.At an archeological excavation,a skeleton is found next to a campfire with some wood ash.If 100 g of carbon from the ash in the campfire emits betas at a rate of 40 per hour,how old is the campfire?

Accepted Answer

A) 44,000 years 
B) 64,000 years 
C) 98,000 years 
D) 230,000 years 
E) 4,500,000 years 
A) 44,000 years 
B) 64,000 years 
C) 98,000 years 
D) 230,000 years 
E) 4,500,000 years

Question 12

Assuming that 200 MeV of energy is released per fission,calculate the total energy released in the fission of 1 g of 235U.

Accepted Answer

A) 2.28 * 104 kW h. 
B) 4.98 * 104 kW h. 
C) 2.28 * 105 kW h. 
D) 1.49 * 106 kW h. 
A) 2.28 * 104 kW h. 
B) 4.98 * 104 kW h. 
C) 2.28 * 105 kW h. 
D) 1.49 * 106 kW h.

Question 13

Sirius,the brightest star in the night sky coverts 3.216 * 1018 kg of its mass to energy every year.How does the luminosity (power radiated)of Sirius compare to that of the sun? Lsun = 3.906 * 1026 W

Accepted Answer

A) 17.6Lsun 
B) 23.5Lsun 
C) 3.56Lsun 
D) 36.7Lsun 
E) 42.0Lsun 
A) 17.6Lsun 
B) 23.5Lsun 
C) 3.56Lsun 
D) 36.7Lsun 
E) 42.0Lsun

Question 14

A certain radioactive isotope decays to one fourth of its original amount in 4.0 hours.What is its half life?

Accepted Answer

A) 1.4 hours 
B) 2.0 hours 
C) 2.5 hours 
D) 3.4 hours 
A) 1.4 hours 
B) 2.0 hours 
C) 2.5 hours 
D) 3.4 hours

Question 15

An iron isotope of iron,56Fe,has a binding energy per nucleon of 8.791 MeV.What is its mass? (The mass of an hydrogen atom is 1.007825 u,the mass of a neutron is 1.008665 u,and the atomic mass unit is 1 u = 931.5 MeV.The number of protons in the iron nucleus is 26.)

Accepted Answer

A) 26.20345 u 
B) 30.23475 u 
C) 55.93494 u 
D) 56.46340 u 
E) 56.99186 u 
A) 26.20345 u 
B) 30.23475 u 
C) 55.93494 u 
D) 56.46340 u 
E) 56.99186 u

Question 16

A Geiger counter initially records 9876 counts per second.After 45 minutes it records 1234 counts/s.Ignore any uncertainty in the counts and find the half-life of the material.

Accepted Answer

A) 900 s 
B) 950 s 
C) 1300 s 
D) 1350 s 
E) 2072 s 
A) 900 s 
B) 950 s 
C) 1300 s 
D) 1350 s 
E) 2072 s

Question 17

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 mass of 235U consumed each day.

Accepted Answer

A) 1.05 kg 
B) 2.63 kg 
C) 4.89 kg 
D) 6.58 kg 
E) 7.11 kg 
A) 1.05 kg 
B) 2.63 kg 
C) 4.89 kg 
D) 6.58 kg 
E) 7.11 kg

Question 18

Betelgeuse has a luminosity (power radiated)135,000 times that of the Sun,which emits energy at the rate of 3.906 * 1026 W.How much of its mass is being converted to energy in each year?

Accepted Answer

A) 1.85 * 1022 kg 
B) 7.70 * 1020 kg 
C) 1.37 * 1017 kg 
D) 5.85 * 1014 kg 
E) 5.06 * 1019 kg 
A) 1.85 * 1022 kg 
B) 7.70 * 1020 kg 
C) 1.37 * 1017 kg 
D) 5.85 * 1014 kg 
E) 5.06 * 1019 kg

Question 19

U-238 has a half-life of 4.5 billion years and a present day abundance of 99.3%.U-235 has a half-life of 0.7 billion years and a present day abundance of 0.7%.Assuming a steady rate of decay,how long ago did these two isotopes have the same abundance?

Accepted Answer

A) 4.1 billion years ago 
B) 5.2 billion years ago 
C) 5.9 billion years ago 
D) 8.4 billion years ago 
E) 9.9 billion years ago 
A) 4.1 billion years ago 
B) 5.2 billion years ago 
C) 5.9 billion years ago 
D) 8.4 billion years ago 
E) 9.9 billion years ago

Question 20

A radioactive atom emits an alpha particle.When this occurs,what happens to the mass number of the atom?

Accepted Answer

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

Exam 40: Nuclear Physics

A certain radioactive isotope decays to one sixteenth of its original amount in 4.0 hours.What is its half-life?

Which of the following is true about strong force?

When 21083Bi decays its half life is 5.0 seconds.What is the activity in Bq (disintegrations per second)of one mole?

The half-life of Co-57 is 271.8 days;calculate the decay constant.

Assuming that a neutron star is as dense as an atomic nucleus,estimate the mass of a neutron star having a diameter of 10 km.

What is the surface area,approximately,of a Lead-208 nucleus (Z = 82)?

In 1991 a frozen body of an "Iceman" was found in the Italian Alps.The fraction of compared to found in the body's bones,hair,and leather clothing was 6.94 * 10-13.The half-life of is 5,730 years and the ratio of to in living organisms is 1 to 7.41 *1011.When did the Iceman die?

Atoms consist of protons,neutrons,and electrons.Which determines an element of the periodic table?

A drug containing with an activity of 2.00 μ\muμ Ci is to be injected into a patient at 11:00 am.A sample is prepared 4.00 hours before the injection (at 7:00 am).The activity of the drug have at the preparation time (7:00 am)was 3.16 μ\muμ Ci.What is the mean lifetime of ?

A Geiger counter placed next to a radioactive sample produces 200 counts per minute.One hour later,the Geiger counter reads 180 counts per minute.What is the half-life of the radioactive sample?

Assuming that 200 MeV of energy is released per fission,calculate the total energy released in the fission of 1 g of 235U.

Sirius,the brightest star in the night sky coverts 3.216 * 1018 kg of its mass to energy every year.How does the luminosity (power radiated)of Sirius compare to that of the sun? Lsun = 3.906 * 1026 W

A certain radioactive isotope decays to one fourth of its original amount in 4.0 hours.What is its half life?

An iron isotope of iron,56Fe,has a binding energy per nucleon of 8.791 MeV.What is its mass? (The mass of an hydrogen atom is 1.007825 u,the mass of a neutron is 1.008665 u,and the atomic mass unit is 1 u = 931.5 MeV.The number of protons in the iron nucleus is 26.)

A Geiger counter initially records 9876 counts per second.After 45 minutes it records 1234 counts/s.Ignore any uncertainty in the counts and find the half-life of the material.

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 mass of 235U consumed each day.

Betelgeuse has a luminosity (power radiated)135,000 times that of the Sun,which emits energy at the rate of 3.906 * 1026 W.How much of its mass is being converted to energy in each year?

U-238 has a half-life of 4.5 billion years and a present day abundance of 99.3%.U-235 has a half-life of 0.7 billion years and a present day abundance of 0.7%.Assuming a steady rate of decay,how long ago did these two isotopes have the same abundance?

A radioactive atom emits an alpha particle.When this occurs,what happens to the mass number of the atom?

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When ²¹⁰₈₃Bi decays its half life is 5.0 seconds.What is the activity in Bq (disintegrations per second)of one mole?

Assuming that 200 MeV of energy is released per fission,calculate the total energy released in the fission of 1 g of ²³⁵U.

Sirius,the brightest star in the night sky coverts 3.216 * 10¹⁸ kg of its mass to energy every year.How does the luminosity (power radiated)of Sirius compare to that of the sun? L_sun = 3.906 * 10²⁶ W

An iron isotope of iron,⁵⁶Fe,has a binding energy per nucleon of 8.791 MeV.What is its mass? (The mass of an hydrogen atom is 1.007825 u,the mass of a neutron is 1.008665 u,and the atomic mass unit is 1 u = 931.5 MeV.The number of protons in the iron nucleus is 26.)

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 mass of ²³⁵U consumed each day.

Betelgeuse has a luminosity (power radiated)135,000 times that of the Sun,which emits energy at the rate of 3.906 * 10²⁶ W.How much of its mass is being converted to energy in each year?