Question 1

It is often possible to use the atomic masses when calculating the binding energy of a nucleus.The reason for this is

Accepted Answer

The electron masses cancel out when calculating the binding energy of a nucleus because electrons are not present inside the nucleus. The atomic mass is the sum of the masses of protons, neutrons, and electrons in an atom, but when calculating the binding energy of a nucleus, the only relevant masses are those of the protons and neutrons. Therefore, using the atomic masses is often possible and convenient for calculating the binding energy of a nucleus.

Question 2

What value of Z (atomic number)and A (mass number)result in the following gamma decay?

Accepted Answer

The answer of What value of Z (atomic number)and A...

Question 3

The Q value for the following reaction, ,is (in MeV) M(alpha)= 4.002 603 u M(Be)= 9.012 182 u m(n.= 1.008 665 u M(C)= 12.000 00 u 1 u = 1.66 × 10−²⁷ kg

Accepted Answer

The answer of The Q value for the following reaction,...

Question 4

The radius of an approximately spherical nucleus is given by r =

Accepted Answer

The radius of a nucleus can be approximated by the empirical formula $r=r_0A^{1/3}$, where $r_0$ is a constant and $A$ is the atomic mass number of the nucleus. Using this formula and substituting $A=Z+N$ (where $Z$ is the atomic number and $N$ is the number of neutrons), we get $r=r_0(A)^{1/3}=r_0(Z+N)^{1/3}=r_0Z^{1/3}(1+(N/Z))^{1/3}$. Since $N$ and $Z$ are integers, we can approximate the expression as $r=r_0Z^{1/3}(1+1.5N/Z)$, which simplifies to $r=r_0Z^{1/3}(1+1.5(A-Z)/A)$. Plugging in the values given, we get $r=r_0A^{1/3}(1.2-0.6Z/A)$, which corresponds to choice D.

Question 5

It is often possible to use atomic masses when calculating the binding energy of a nucleus.This is not true for calculating the Q value for the e⁺ decay process since

Accepted Answer

In the e⁺ decay process, electrons are involved as opposed to just nuclei. Since electrons have nonzero mass, their masses cannot cancel out when calculating the Q value.

Question 6

Two nuclei which share the same atomic number Z always are

Accepted Answer

Nuclei that have the same atomic number are isotopes. This means they have the same number of protons but may have a different number of neutrons, leading to different atomic masses. Isotopes can be stable or unstable, and some may be radioactive.

Question 7

Which of the effects listed below is not a major effect influencing the binding energy of the nucleus in the liquid-drop model?

Accepted Answer

The quantum number effect is not a major factor influencing the binding energy of the nucleus in the liquid-drop model. The other factors listed (volume effect, surface effect, Coulomb repulsion effect, and symmetry effect) are all significant and contribute to the overall binding energy.

Question 8

Because we know that the half-lives of many radioactive isotopes are millions of years,we can deduce that

Accepted Answer

The long half-lives of radioactive isotopes imply that they decay slowly over time. Therefore, if these isotopes are present now, there must have been a larger quantity of them in the past, including when life began on Earth.

Question 9

In beta decays

Accepted Answer

Beta decay involves the emission of either an electron (i.e. beta minus decay) or a positron (i.e. beta plus decay) from the nucleus. In beta minus decay, a neutron in the nucleus is transformed into a proton, while also emitting an electron and an antineutrino. In beta plus decay, a proton in the nucleus is transformed into a neutron, while also emitting a positron and a neutrino. Therefore, only (a) or (b) can occur in beta decay, which corresponds to the choices given in option E. Option C is incorrect because electrons are not present in the nucleus.

Question 10

Two nuclei may have equal Z,but different A,because they contain

Accepted Answer

Z represents the atomic number which is the number of protons in the nucleus. Therefore, if two nuclei have equal Z, they have the same number of protons. However, A represents the mass number which is the total number of protons and neutrons in the nucleus. Therefore, two nuclei can have the same number of protons but different numbers of neutrons, resulting in different values of A.

Question 11

How can a nucleus be described by particular values of A,Z and N when the mass of the nucleus is not equal to Zm_p + Nm_n,where m_p and m_n are the masses of free protons and neutrons?

Accepted Answer

A nucleus can be described by particular values of A, Z, and N as they represent the number of particles of given types (protons and neutrons) in the nucleus. The mass of the nucleus is not equal to the sum of the masses of its constituent particles (protons and neutrons) because the binding energy (or mass defect) is taken into account. Therefore, A, Z, and N only describe the number of particles in the nucleus, not their masses in a bound state.

Question 12

The reaction energy associated with a nuclear reaction is

Accepted Answer

The reaction energy associated with a nuclear reaction is the total change in rest energy as a result of the reaction. This includes the energy released or absorbed during the process of splitting or fusing the atomic nuclei.

Question 13

What is the disintegration energy (in MeV)associated with this spontaneous decay? M_Nd = 143.910 083 u M_Ce = 139.905 434 u M_He = 4.002 603 u 1 u = 1.66 × 10−²⁷ kg

Accepted Answer

The answer of What is the disintegration energy (in MeV)associated...

Question 14

The chart below shows part of the radioactive series beginning with the isotope 
)The isotope marked with an X is

Accepted Answer

The answer of The chart below shows part of the...

Question 15

Rutherford's experiment,in which he fired alpha particles of 7.7 MeV kinetic energy at a thin gold foil,showed that nuclei were very much smaller than the size of an atom because

Accepted Answer

Rutherford's experiment showed that some alpha particles were deflected backwards, indicating that the positive charge of the atom was concentrated in a tiny nucleus at the center, rather than being spread out throughout the atom's volume. This led to the conclusion that nuclei were very much smaller than the size of an atom. Option A refers to alpha particles passing through the foil undeflected, which also occurred but didn't provide evidence for the small size of the nucleus. Option C refers to alpha particles being captured by gold nuclei, which also occurred but didn't provide evidence for the small size of the nucleus. Option D refers to a hypothetical scenario where the alpha particles couldn't get closer than 10^-10 m to the gold nuclei, but this wasn't observed in the actual experiment. Option E is incorrect since alpha particles don't split into deuterium nuclei.

Question 16

According to the shell model,binding energy per nucleon is greater when N or Z is equal to one of the numbers below except for

Accepted Answer

The shell model predicts increased binding energy when the numbers of protons or neutrons in a nucleus correspond to closed shells, which occur at N/Z = 2, 8, 20, 28, 50, 82, and 126. Thus, choices A, B, D, and E all correspond to closed shells and would be expected to have higher binding energies. Choice C, however, is not a closed shell and therefore would not be expected to have higher binding energy.

Question 17

When a neutron decays,a proton and an electron are observed.When the electrons emitted from a sample of neutrons are observed,they are found to have different kinetic energies.This was accounted for by

Accepted Answer

The observation of different kinetic energies of the electrons emitted during neutron decay cannot be explained solely by the conservation laws of momentum and energy. It was discovered that a new particle, the neutrino, was also being emitted during the decay process, carrying away some of the energy and momentum. Introducing the neutrino into the model allows for conservation of momentum and energy, and explains the observed variation in electron kinetic energies.

Question 18

In nuclear magnetic resonance,nuclei absorb energy when flipping between nuclear

Accepted Answer

Nuclei in nuclear magnetic resonance absorb energy when flipping between their spin states. This is because NMR is based on the interaction between the magnetic field and the spin of the nucleus.

Question 19

Two nuclei which share the same mass number A always are (Hint: Eliminate any wrong answers. )

Accepted Answer

Nuclei with the same mass number A but different atomic numbers are called isobars.

Question 20

Heavy nuclei are unstable because

Accepted Answer

Heavy nuclei have a larger number of protons and neutrons, resulting in a strong repulsive Coulomb force between protons. However, the nuclear force is stronger than the Coulomb repulsion at distances less than 2 femtometers (fm). This force falls off rapidly at greater distances, hence heavy nuclei are unstable due to the imbalance between the strong nuclear force and the weak Coulomb repulsion.

Quiz 44: Nuclear Structure

It is often possible to use the atomic masses when calculating the binding energy of a nucleus.The reason for this is

What value of Z (atomic number) and A (mass number) result in the following gamma decay?

The Q value for the following reaction, ,is (in MeV) M(alpha) = 4.002 603 u M(Be) = 9.012 182 u m(n.= 1.008 665 u M(C) = 12.000 00 u 1 u = 1.66 × 10−²⁷ kg

The radius of an approximately spherical nucleus is given by r =

It is often possible to use atomic masses when calculating the binding energy of a nucleus.This is not true for calculating the Q value for the e⁺ decay process since

Two nuclei which share the same atomic number Z always are

Which of the effects listed below is not a major effect influencing the binding energy of the nucleus in the liquid-drop model?

Because we know that the half-lives of many radioactive isotopes are millions of years,we can deduce that

In beta decays

Two nuclei may have equal Z,but different A,because they contain

How can a nucleus be described by particular values of A,Z and N when the mass of the nucleus is not equal to Zm_p + Nm_n,where m_p and m_n are the masses of free protons and neutrons?

The reaction energy associated with a nuclear reaction is

What is the disintegration energy (in MeV) associated with this spontaneous decay? M_Nd = 143.910 083 u M_Ce = 139.905 434 u M_He = 4.002 603 u 1 u = 1.66 × 10−²⁷ kg

The chart below shows part of the radioactive series beginning with the isotope ) The isotope marked with an X is

Rutherford's experiment,in which he fired alpha particles of 7.7 MeV kinetic energy at a thin gold foil,showed that nuclei were very much smaller than the size of an atom because

According to the shell model,binding energy per nucleon is greater when N or Z is equal to one of the numbers below except for

When a neutron decays,a proton and an electron are observed.When the electrons emitted from a sample of neutrons are observed,they are found to have different kinetic energies.This was accounted for by

In nuclear magnetic resonance,nuclei absorb energy when flipping between nuclear

Two nuclei which share the same mass number A always are (Hint: Eliminate any wrong answers. )

Heavy nuclei are unstable because

Quiz 44: Nuclear Structure

It is often possible to use the atomic masses when calculating the binding energy of a nucleus.The reason for this is

What value of Z (atomic number) and A (mass number) result in the following gamma decay?

The Q value for the following reaction, ,is (in MeV) M(alpha) = 4.002 603 u M(Be) = 9.012 182 u m(n.= 1.008 665 u M(C) = 12.000 00 u 1 u = 1.66 × 10−27 kg

The radius of an approximately spherical nucleus is given by r =

It is often possible to use atomic masses when calculating the binding energy of a nucleus.This is not true for calculating the Q value for the e+ decay process since

Two nuclei which share the same atomic number Z always are

Which of the effects listed below is not a major effect influencing the binding energy of the nucleus in the liquid-drop model?

Because we know that the half-lives of many radioactive isotopes are millions of years,we can deduce that

In beta decays

Two nuclei may have equal Z,but different A,because they contain

How can a nucleus be described by particular values of A,Z and N when the mass of the nucleus is not equal to Zmp + Nmn,where mp and mn are the masses of free protons and neutrons?

The reaction energy associated with a nuclear reaction is

What is the disintegration energy (in MeV) associated with this spontaneous decay? MNd = 143.910 083 u MCe = 139.905 434 u MHe = 4.002 603 u 1 u = 1.66 × 10−27 kg

The chart below shows part of the radioactive series beginning with the isotope ) The isotope marked with an X is

Rutherford's experiment,in which he fired alpha particles of 7.7 MeV kinetic energy at a thin gold foil,showed that nuclei were very much smaller than the size of an atom because

According to the shell model,binding energy per nucleon is greater when N or Z is equal to one of the numbers below except for

When a neutron decays,a proton and an electron are observed.When the electrons emitted from a sample of neutrons are observed,they are found to have different kinetic energies.This was accounted for by

In nuclear magnetic resonance,nuclei absorb energy when flipping between nuclear

Two nuclei which share the same mass number A always are (Hint: Eliminate any wrong answers. )

Heavy nuclei are unstable because

The Q value for the following reaction, ,is (in MeV) M(alpha) = 4.002 603 u M(Be) = 9.012 182 u m(n.= 1.008 665 u M(C) = 12.000 00 u 1 u = 1.66 × 10−²⁷ kg

It is often possible to use atomic masses when calculating the binding energy of a nucleus.This is not true for calculating the Q value for the e⁺ decay process since

How can a nucleus be described by particular values of A,Z and N when the mass of the nucleus is not equal to Zm_p + Nm_n,where m_p and m_n are the masses of free protons and neutrons?

What is the disintegration energy (in MeV) associated with this spontaneous decay? M_Nd = 143.910 083 u M_Ce = 139.905 434 u M_He = 4.002 603 u 1 u = 1.66 × 10−²⁷ kg