Question 1

Starting with a sample of pure 66Cu, 7/8 of it decays into Zn in 15 minutes. The corresponding half-life is:

Accepted Answer

A)   15 minutes
B)   5 minutes
C)   7 minutes
D)   3.75 minutes
E)   10 minutes

Question 2

Magnesium has atomic number 12, hydrogen has atomic number 1, and helium has atomic number 2. In the nuclear reaction 24Mg + 2H  →\rightarrow→  ( )  + 4He the missing quantity is:

Accepted Answer

A)   23Na (Z = 11) 
B)   22Ne (Z = 10) 
C)   21Na (Z = 11) 
D)   21Ne (Z = 10) 
E)   22Na (Z = 11)

Question 3

A femtometer is:

Accepted Answer

A)   larger than 10-9 m
B)   10-9 m
C)   10-12 m
D)   10-15 m
E)   10-18 m

Question 4

At the end of 14 min, 1/16 of a sample of radioactive polonium remains. The corresponding half-life is:

Accepted Answer

A)   (7/8)  min
B)   (8/7)  min
C)   (7/4)  min
D)   (7/2)  min
E)   (14/3)  min

Question 5

210Bi (an isotope of bismuth)  has a half-life of 5.0 days. The time for three-quarters of a sample of 210Bi to decay is:

Accepted Answer

A)   2.5 days
B)   10 days
C)   15 days
D)   20 days
E)   3.75 days

Question 6

A nucleus with a mass number of 64 has a mean radius of about:

Accepted Answer

A)   4.8 fm
B)   19 fm
C)   77 fm
D)   260 fm
E)   2.6* 105 fm

Question 7

A proton in a large nucleus:

Accepted Answer

A)   attracts all other protons
B)   repels all other protons
C)   repels all neutrons
D)   attracts some protons and repels others
E)   attracts some neutrons and repels others

Question 8

The mass of a neutron:

Accepted Answer

A)   equals that of an electron
B)   equals that of a proton
C)   is a little more than that of a proton
D)   is exactly that of a proton plus an electron
E)   is as yet unmeasured

Question 9

A radium atom, 226Ra (Z = 86) , emits an alpha particle. The number of protons in the resulting atom is:

Accepted Answer

A)   84
B)   85
C)   86
D)   88
E)   some other number

Question 10

Volumes of atomic nuclei are proportional to:

Accepted Answer

A)   the mass number
B)   the atomic number
C)   the total nuclear spin
D)   the number of neutrons
E)   none of these

Question 11

Aluminum has atomic number 13, helium has atomic number 2, and silicon has atomic number 14. In the nuclear reaction 27Al + 4He →\rightarrow→ 30Si + ( )  the missing particle is:

Accepted Answer

A)   an  α\alphaα  particle
B)   a positron
C)   a electron
D)   proton
E)   neutron  D

Question 12

The graph shows the activity R as a function of the time t for three radioactive samples. Rank the samples according to their half-lives, shortest to longest.

Accepted Answer

A)   1, 2 ,3
B)   1, 3, 2
C)   2, 1, 3
D)   2, 3, 1
E)   3, 1, 2

Question 13

Some alpha emitters have longer half-lives than others because:

Accepted Answer

A)   their alpha particles have greater mass
B)   their alpha particles have less mass
C)   their barriers to decay are higher and wider
D)   their barriers to decay are lower and narrower
E)   their decays include the emission of a photon

Question 14

The smallest particle of any chemical element that can exist by itself and yet retain the qualities that distinguish it as that element is:

Accepted Answer

A)   an electron
B)   a proton
C)   a neutron
D)   an atom
E)   a molecule

Question 15

Radioactive 90Sr has a half-life of 30 years. What percent of a sample of 90Sr will remain after 60 years?

Accepted Answer

A)   0%
B)   25%
C)   50%
D)   75%
E)   14% B

Question 16

The atomic number of an element is:

Accepted Answer

A)   the whole number nearest to its mass
B)   the number of protons in its nucleus
C)   the nearest whole number of hydrogen atoms having the same mass as a single atom of the given element
D)   the number of neutrons in its nucleus
E)   its order of discovery

Question 17

Let Z denote the atomic number and A denote the mass number of a nucleus. The number of neutrons in this nucleus is:

Accepted Answer

A)   Z
B)   A - Z
C)   A - 2Z
D)   A
E)   2A - Z B

Question 18

Of the three common types of radiation (alpha, beta, gamma)  from radioactive sources, electric charge is carried by:

Accepted Answer

A)   only beta and gamma
B)   only beta
C)   only alpha and gamma
D)   only alpha
E)   only alpha and beta

Question 19

Bromine, with atomic mass 79.942 u, is composed of nearly equal amounts of two isotopes, one of which contains 79 nucleons per atom. The mass number of the other isotope is:

Accepted Answer

A)   78
B)   79
C)   80
D)   81
E)   82

Question 20

The isotopes of an element:

Accepted Answer

A)   cannot be separated at all
B)   occur well separated in nature
C)   have similar chemical behavior
D)   cannot be separated by physical methods
E)   have equal masses

Exam 42: Nuclear Physics

Starting with a sample of pure 66Cu, 7/8 of it decays into Zn in 15 minutes. The corresponding half-life is:

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Magnesium has atomic number 12, hydrogen has atomic number 1, and helium has atomic number 2. In the nuclear reaction 24Mg + 2H →\rightarrow→ ( ) + 4He the missing quantity is:

Correct AnswerverifiedShow Answer

A femtometer is:

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At the end of 14 min, 1/16 of a sample of radioactive polonium remains. The corresponding half-life is:

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210Bi (an isotope of bismuth) has a half-life of 5.0 days. The time for three-quarters of a sample of 210Bi to decay is:

Correct AnswerverifiedShow Answer

A nucleus with a mass number of 64 has a mean radius of about:

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A proton in a large nucleus:

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The mass of a neutron:

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A radium atom, 226Ra (Z = 86) , emits an alpha particle. The number of protons in the resulting atom is:

Correct AnswerverifiedShow Answer

Volumes of atomic nuclei are proportional to:

Correct AnswerverifiedShow Answer

Aluminum has atomic number 13, helium has atomic number 2, and silicon has atomic number 14. In the nuclear reaction 27Al + 4He →\rightarrow→ 30Si + ( ) the missing particle is:

Correct AnswerverifiedD

The graph shows the activity R as a function of the time t for three radioactive samples. Rank the samples according to their half-lives, shortest to longest.

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Some alpha emitters have longer half-lives than others because:

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The smallest particle of any chemical element that can exist by itself and yet retain the qualities that distinguish it as that element is:

Correct AnswerverifiedShow Answer

Radioactive 90Sr has a half-life of 30 years. What percent of a sample of 90Sr will remain after 60 years?

Correct AnswerverifiedB

The atomic number of an element is:

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Let Z denote the atomic number and A denote the mass number of a nucleus. The number of neutrons in this nucleus is:

Correct AnswerverifiedB

Of the three common types of radiation (alpha, beta, gamma) from radioactive sources, electric charge is carried by:

Correct AnswerverifiedShow Answer

Bromine, with atomic mass 79.942 u, is composed of nearly equal amounts of two isotopes, one of which contains 79 nucleons per atom. The mass number of the other isotope is:

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The isotopes of an element:

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Starting with a sample of pure ⁶⁶Cu, 7/8 of it decays into Zn in 15 minutes. The corresponding half-life is:

Correct Answer
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Magnesium has atomic number 12, hydrogen has atomic number 1, and helium has atomic number 2. In the nuclear reaction ²⁴Mg + ²H $\rightarrow$ ( ) + ⁴He the missing quantity is:

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²¹⁰Bi (an isotope of bismuth) has a half-life of 5.0 days. The time for three-quarters of a sample of ²¹⁰Bi to decay is:

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A radium atom, ²²⁶Ra (Z = 86) , emits an alpha particle. The number of protons in the resulting atom is:

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Aluminum has atomic number 13, helium has atomic number 2, and silicon has atomic number 14. In the nuclear reaction ²⁷Al + ⁴He $\rightarrow$ ³⁰Si + ( ) the missing particle is:

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D

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Radioactive ⁹⁰Sr has a half-life of 30 years. What percent of a sample of ⁹⁰Sr will remain after 60 years?

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B

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B

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