Question 1

The nuclear radius of 27Co is approximately

Accepted Answer

A)  1.2 fm. 
B)  3.6 fm. 
C)  4.5 fm. 
D)  6.0 fm. 
E)  None of the above responses is correct. 
A)  1.2 fm. 
B)  3.6 fm. 
C)  4.5 fm. 
D)  6.0 fm. 
E)  None of the above responses is correct. B

Question 2

The graphs here show the number of undecayed nuclei as a function of time for a radioactive element. The graph corresponding to elements having the smaller decay constant is

Accepted Answer

A)  A 
B)  B 
C)  C 
D)  D 
E)  E 
A)  A 
B)  B 
C)  C 
D)  D 
E)  E E

Question 3

The significant forces in determining the structure of nuclei are

Accepted Answer

A)  coulomb and gravitational. 
B)  gravitational and weak. 
C)  strong and weak. 
D)  coulomb and strong. 
E)  gravitational, coulomb, and strong. 
A)  coulomb and gravitational. 
B)  gravitational and weak. 
C)  strong and weak. 
D)  coulomb and strong. 
E)  gravitational, coulomb, and strong. D

Question 4

In a ${ } _ { 56 } ^ { 135 } \mathrm { Ba }$ nucleus, the numbers of protons, neutrons, and electrons are

Accepted Answer

A)  56, 79, and 135, respectively. 
B)  56, 79, and 0, respectively. 
C)  79, 56, and 135, respectively. 
D)  79, 56, and 0, respectively. 
E)  None of the previous answers is correct. 
A)  56, 79, and 135, respectively. 
B)  56, 79, and 0, respectively. 
C)  79, 56, and 135, respectively. 
D)  79, 56, and 0, respectively. 
E)  None of the previous answers is correct.

Question 5

The number of 131I (half-life of 8.04 days) nuclei necessary to produce an activity of 5.0 mCi is

Accepted Answer

A)  8.91 * 1014. 
B)  1.85 * 1014. 
C)  3.09 * 1012. 
D)  5.01 * 106. 
E)  5.01 * 103. 
A)  8.91 * 1014. 
B)  1.85 * 1014. 
C)  3.09 * 1012. 
D)  5.01 * 106. 
E)  5.01 * 103.

Question 6

During $\beta ^ { + }$ decay,

Accepted Answer

A)  a neutron is ejected from the nucleus. 
B)  a neutron is transformed to a proton. 
C)  a proton is transformed to a neutron. 
D)  a proton is ejected from the nucleus. 
E)  None of the above is true. 
A)  a neutron is ejected from the nucleus. 
B)  a neutron is transformed to a proton. 
C)  a proton is transformed to a neutron. 
D)  a proton is ejected from the nucleus. 
E)  None of the above is true.

Question 7

The radioactivity of a certain radioisotope decreases to one-half in 1.0 hour. Three hours later, its radioactivity, compared with that at the beginning of the first hour, is

Accepted Answer

A)  1/2. 
B)  3/2. 
C)  1/4. 
D)  1/6. 
E)  1/8. 
A)  1/2. 
B)  3/2. 
C)  1/4. 
D)  1/6. 
E)  1/8.

Question 8

The graphs here show the number of undecayed nuclei as a function of time for a radioactive element. The graphs corresponding to elements having the same half-life are

Accepted Answer

A)  A and B. 
B)  A and C. 
C)  A and D. 
D)  B and C. 
E)  B and D. 
A)  A and B. 
B)  A and C. 
C)  A and D. 
D)  B and C. 
E)  B and D.

Question 9

The graph here shows the number of undecayed nuclei as a function of time for a radioactive element. The number of undecayed nuclei at t = 16 s is

Accepted Answer

A)  30 
B)  23 
C)  13 
D)  5.6 
E)  More information is needed to work out the answer. 
A)  30 
B)  23 
C)  13 
D)  5.6 
E)  More information is needed to work out the answer.

Question 10

If the parent nucleus has N neutrons and Z protons, after an $\alpha$ decay, the daughter nucleus has respective neutron and proton numbers of

Accepted Answer

A)  N and Z - 1. 
B)  N and Z + 1. 
C)  N - 2 and Z - 2. 
D)  N - 1 and Z - 1. 
E)  N and Z. 
A)  N and Z - 1. 
B)  N and Z + 1. 
C)  N - 2 and Z - 2. 
D)  N - 1 and Z - 1. 
E)  N and Z.

Question 11

If 40 g of substance of half-life 5.0 hours remain from an original sample of 1.28 kg, the time that has passed is

Accepted Answer

A)  1.0 hour. 
B)  20 hours. 
C)  25 hours. 
D)  80 hours. 
E)  160 hours. 
A)  1.0 hour. 
B)  20 hours. 
C)  25 hours. 
D)  80 hours. 
E)  160 hours.

Question 12

The nucleus with the larger binding energy per nucleon is

Accepted Answer

A)  238U. 
B)  197Au. 
C)  62Ni. 
D)  4He. 
E)  2H. 
A)  238U. 
B)  197Au. 
C)  62Ni. 
D)  4He. 
E)  2H.

Question 13

The mass of a typical nucleus is

Accepted Answer

A)  somewhat less than the sum of the masses of its constituents. 
B)  somewhat more than the sum of the masses of its constituents. 
C)  equal to the sum of the masses of its constituents. 
D)  None of the previous responses is a valid generalization. 
A)  somewhat less than the sum of the masses of its constituents. 
B)  somewhat more than the sum of the masses of its constituents. 
C)  equal to the sum of the masses of its constituents. 
D)  None of the previous responses is a valid generalization.

Question 14

In terms of increasing penetrating ability, the three kinds of rays emitted by radioactive isotopes are

Accepted Answer

A)  $\alpha , \beta , \gamma$ 
B)  $\beta , \gamma , \alpha$ 
C)  $\gamma , \alpha , \beta$ 
D)  $\beta , \alpha , \gamma$ 
E)  All have the same penetrating ability. 
A)  $\alpha , \beta , \gamma$ 
B)  $\beta , \gamma , \alpha$ 
C)  $\gamma , \alpha , \beta$ 
D)  $\beta , \alpha , \gamma$ 
E)  All have the same penetrating ability.

Question 15

In terms of charge, the $\alpha , \beta , \gamma$ rays emitted by radioactive isotopes are, respectively

Accepted Answer

A)  positive, neutral, and negative. 
B)  positive, negative, and neutral. 
C)  negative, neutral, and positive. 
D)  negative, positive, and neutral. 
E)  neutral, negative, and positive. 
A)  positive, neutral, and negative. 
B)  positive, negative, and neutral. 
C)  negative, neutral, and positive. 
D)  negative, positive, and neutral. 
E)  neutral, negative, and positive.

Question 16

The radioactive decay mode where the daughter and the parent nuclides are the same element is

Accepted Answer

A)  $\alpha$ decay. 
B)  $\beta$ decay. 
C)  $\gamma$ decay. 
D)  None of the previous responses is valid. 
A)  $\alpha$ decay. 
B)  $\beta$ decay. 
C)  $\gamma$ decay. 
D)  None of the previous responses is valid.

Question 17

In comparison with an electron, a proton has larger

Accepted Answer

A)  mass and size. 
B)  spin. 
C)  magnetic moment. 
D)  All of the previous answers are correct. 
E)  None of the previous answers is correct. 
A)  mass and size. 
B)  spin. 
C)  magnetic moment. 
D)  All of the previous answers are correct. 
E)  None of the previous answers is correct.

Question 18

If the parent nucleus has N neutrons and Z protons, after the ejection of a positron (anti-electron) in a $\beta$ decay, the daughter nucleus has respective neutron and proton numbers of

Accepted Answer

A)  N - 1 and Z - 1. 
B)  N - 1 and Z + 1. 
C)  N and Z - 2. 
D)  N + 1 and Z + 1. 
E)  N + 1 and Z - 1. 
A)  N - 1 and Z - 1. 
B)  N - 1 and Z + 1. 
C)  N and Z - 2. 
D)  N + 1 and Z + 1. 
E)  N + 1 and Z - 1.

Question 19

If the half-life of a material is 45 years, how much will be left after 100 years?

Accepted Answer

A)  less than a quarter. 
B)  more than a quarter. 
C)  less than half. 
D)  more than half. 
E)  More information is needed to work out the answer. 
A)  less than a quarter. 
B)  more than a quarter. 
C)  less than half. 
D)  more than half. 
E)  More information is needed to work out the answer.

Question 20

At a particular time, a radioactive source A has a strength of 1.60 *1011 Bq and a half-life of 8.00 days, and a radioactive source B has a strength of 6.40 *1011 Bq. The two sources have the same strength 30.0 days later. The half-life of source B is

Accepted Answer

A)  35.7 days. 
B)  24.7 days. 
C)  17.2 days. 
D)  7.53 days. 
E)  5.22 days. 
A)  35.7 days. 
B)  24.7 days. 
C)  17.2 days. 
D)  7.53 days. 
E)  5.22 days.

Exam 40: Nuclei

The nuclear radius of 27Co is approximately

The graphs here show the number of undecayed nuclei as a function of time for a radioactive element. The graph corresponding to elements having the smaller decay constant is

The significant forces in determining the structure of nuclei are

In a 56135Ba{ } _ { 56 } ^ { 135 } \mathrm { Ba }56135​Ba nucleus, the numbers of protons, neutrons, and electrons are

The number of 131I (half-life of 8.04 days) nuclei necessary to produce an activity of 5.0 mCi is

During β+\beta ^ { + }β+ decay,

The radioactivity of a certain radioisotope decreases to one-half in 1.0 hour. Three hours later, its radioactivity, compared with that at the beginning of the first hour, is

The graphs here show the number of undecayed nuclei as a function of time for a radioactive element. The graphs corresponding to elements having the same half-life are

The graph here shows the number of undecayed nuclei as a function of time for a radioactive element. The number of undecayed nuclei at t = 16 s is

If the parent nucleus has N neutrons and Z protons, after an α\alphaα decay, the daughter nucleus has respective neutron and proton numbers of

If 40 g of substance of half-life 5.0 hours remain from an original sample of 1.28 kg, the time that has passed is

The nucleus with the larger binding energy per nucleon is

The mass of a typical nucleus is

In terms of increasing penetrating ability, the three kinds of rays emitted by radioactive isotopes are

In terms of charge, the α,β,γ\alpha , \beta , \gammaα,β,γ rays emitted by radioactive isotopes are, respectively

The radioactive decay mode where the daughter and the parent nuclides are the same element is

In comparison with an electron, a proton has larger

If the parent nucleus has N neutrons and Z protons, after the ejection of a positron (anti-electron) in a β\betaβ decay, the daughter nucleus has respective neutron and proton numbers of

If the half-life of a material is 45 years, how much will be left after 100 years?

At a particular time, a radioactive source A has a strength of 1.60 *1011 Bq and a half-life of 8.00 days, and a radioactive source B has a strength of 6.40 *1011 Bq. The two sources have the same strength 30.0 days later. The half-life of source B is

Space, Time, and Mass

Motion Along a Straight Line

Vectors

Motion in Two and Three Dimensions

Newtons Laws of Motion

Further Applications of Newtons Laws

Work and Energy

Conservation of Energy

Gravitation

Systems of Particles

Collisions

Rotation of a Rigid Body

Dynamics of a Rigid Body

Statics and Elasticity

Oscillations

Waves

Sound

Fluid Mechanics

The Ideal Gas

Heat

Thermodynamics

Electric Force and the Electric Charge

The Electric Field

Gauss Law

Electrostatic Potential and Energy

Capacitors and Dielectrics

Currents and Ohms Law

Direct Current Circuits

Magnetic Force and Field

Charges and Currents in Magnetic Fields

Electromagnetic Induction

Alternating Current Circuits

Electromagnetic Waves

Reflection, Refraction, and Optics

Interference and Diffraction

The Theory of Special Relativity

Quanta of Light

Spectral Lines, Bohrs Theory, and Quantum Mechanics

Quantum Structure of Atoms, Molecules, and Solids

Elementary Particles and Cosmology

Filters

The nuclear radius of ²⁷Co is approximately

In a ${ } _ { 56 } ^ { 135 } \mathrm { Ba }$ nucleus, the numbers of protons, neutrons, and electrons are

The number of ¹³¹I (half-life of 8.04 days) nuclei necessary to produce an activity of 5.0 mCi is

During $\beta ^ { + }$ decay,

If the parent nucleus has N neutrons and Z protons, after an $\alpha$ decay, the daughter nucleus has respective neutron and proton numbers of

In terms of charge, the $\alpha , \beta , \gamma$ rays emitted by radioactive isotopes are, respectively

If the parent nucleus has N neutrons and Z protons, after the ejection of a positron (anti-electron) in a $\beta$ decay, the daughter nucleus has respective neutron and proton numbers of

At a particular time, a radioactive source A has a strength of 1.60 10¹¹ Bq and a half-life of 8.00 days, and a radioactive source B has a strength of 6.40 10¹¹ Bq. The two sources have the same strength 30.0 days later. The half-life of source B is