Nuclear and Quantum Physics

Which particle is the exchange particle for the gravitational force?

What is the charge of an alpha particle?

How many generations of quarks and leptons are there in the Standard Model?

Which particle has a lepton number of $+1$ and a charge of $-1e$?

The diagram below illustrates the organization of elementary fermions in the second and third generations of the Standard Model. Labels A and C represent particles with an electric charge of $-1e$, while labels B and D represent particles with an electric charge of $0$. Which label identifies the muon neutrino ($\nu_{\mu}$)?

What is the net charge of an anti-baryon composed of two anti-up quarks and one anti-down quark ($\bar{u}\bar{u}\bar{d}$)?

Which of the following statements about quarks is correct?

What is the main reason heavy nuclei ($Z > 82$) tend to be unstable?

Which of the following quark combinations would result in a baryon with a charge of $+2e$?

A radioactive sample has an initial activity $A_0$. After two half-lives, the activity becomes:

A beam containing alpha ($\alpha$), beta-minus ($\beta^-$), and gamma ($\gamma$) radiation passes through a uniform electric field between two charged plates. The diagram illustrates the paths taken by these radiations. If Path A is directed towards the positively charged plate, which type of radiation follows Path A?

Which of the following properties determines the chemical behavior of an atom?

In a graph of Activity ($A$) versus time ($t$), what does the area under the curve represent?

Which symbol represents a positron in nuclear equations?

Two radioactive samples, $X$ and $Y$, consist of different isotopes but have the same total mass. The molar mass of isotope $X$ is twice the molar mass of isotope $Y$. The half-life of isotope $X$ is one-quarter the half-life of isotope $Y$. What is the ratio of the initial activity of sample $X$ to the initial activity of sample $Y$?

A source emits alpha, beta, and gamma radiation. Which would be most dangerous if the source were ingested (swallowed)?

Identify the missing particle 'X' in the following decay: $^{210}_{84}Po \rightarrow ^{206}_{82}Pb + X$.

A radioactive sample initially contains equal numbers of nuclei of two isotopes, $X$ and $Y$. Isotope $X$ has a half-life of $T$ and decays directly into a stable daughter product by alpha emission. Isotope $Y$ has a half-life of $2T$ and decays directly into a stable daughter product by beta-minus emission. A detector captures all particles emitted by the sample. What is the ratio of the total number of particles (alpha and beta-minus combined) emitted by the sample during the time interval from $t = 0$ to $t = 2T$ to the total number of particles emitted after $t = 2T$?

A radioactive source with a long half-life is used to check the stability of a GM counter. If the counter records $N$ counts in a fixed time interval, the standard deviation of the measurement is $\sqrt{N}$. If we want to reduce the percentage uncertainty by half, by what factor must we increase the counting time?

In a cloud chamber, alpha particles leave thick, straight tracks while beta particles leave thin, wispy tracks. This is because:

Which of the following statements about nuclear forces is true?

In the fission of Uranium-235, which of the following is usually released along with two daughter nuclei?

What is the energy equivalent of $1.0 u$ of mass defect?

Which of the following identifies an isotope?

Which of the following statements about the binding energy of a nucleus is true?

When a U-235 nucleus undergoes fission, the resulting fragments have a total mass of $234.82 \, \text{u}$. The initial mass of the U-235 plus the neutron was $236.05 \, \text{u}$. How much energy was released per fission?

Which of the following characterizes an 'induced' fission reaction?

A $1 \, \text{GW}$ nuclear reactor has an efficiency of $35\%$. How many $^{235}\text{U}$ nuclei must fission per second to maintain this power? (Assume $200 \, \text{MeV}$ per fission)

In stellar nucleosynthesis, the 'Iron Peak' refers to the fact that:

If the binding energy of $^{235}\text{U}$ is $1780 \, \text{MeV}$ and the energy released per fission is $200 \, \text{MeV}$, what is the total binding energy of the fission products?

When white light passes through a cool gas, the resulting spectrum is:

If a photon has a frequency of $1.0 \times 10^{15} \text{ Hz}$, what is its energy? (Use $h = 6.6 \times 10^{-34} \text{ J s}$)

What is the maximum kinetic energy of a photoelectron if the incident photon energy is $E$ and the work function is $\Phi$?

The work function for a certain metal is $4.14 \text{ eV}$. What is this energy in Joules?

In a photoelectric effect experiment, the wavelength of incident light is decreased. What happens to the slope of the graph of $V_s$ (stopping potential) versus $f$ (frequency)?

If an electron transitions from $n=3$ to $n=1$ in a hydrogen atom, and then another electron transitions from $n=3$ to $n=2$, how do the wavelengths of the emitted photons compare?

Which of the following units can be used to express Planck's constant $h$?

If the threshold frequency for a metal is $6.0 \times 10^{14}$ Hz, what is the maximum kinetic energy of electrons emitted when the metal is exposed to light of wavelength $400$ nm?

A hydrogen atom absorbs a photon and is excited from the ground state to the $n=3$ state. It then returns to the ground state. What is the ratio of the energy of the absorbed photon to the lowest energy photon it could emit during de-excitation?

A beam of light with a power of $6.63$ mW consists of photons with a wavelength of $600$ nm. How many photons strike a surface every second?

In an experiment to demonstrate the photoelectric effect, why is the apparatus usually enclosed in a vacuum?

The 'electronvolt' is defined as the work done in moving an electron through a potential difference of:

Which of the following is true for a photon?

The de Broglie wavelength of an electron is $1.0 \times 10^{-10}$ m. What is its momentum? (Use $h = 6.63 \times 10^{-34}$ J s).

What was the main conclusion drawn from the photoelectric effect regarding the nature of light?

A beam of electrons is accelerated through a potential $V$. If the momentum of these electrons is $p$, what is the momentum of electrons accelerated through a potential $4V$?

If an electron transitions from $n=4$ to $n=2$ in a hydrogen atom, and then from $n=2$ to $n=1$, which transition emits a photon with the higher frequency?

An electron is in the $n=3$ state of a hydrogen atom. How many different photon frequencies can be emitted as the electron returns to the ground state?

The photoelectric effect cannot be explained by the classical wave theory of light because the wave theory predicts that:

In the Heisenberg uncertainty principle, the product $\Delta x \Delta p$ is always greater than or equal to $h/4\pi$. If we measure the position of an electron with absolute precision ($\Delta x = 0$), what happens to the uncertainty in momentum?

Which of the following statements about radioactive background radiation is true?

Carbon-14 is often used for radioactive dating. If its half-life is 5730 years, how long will it take for the activity of a sample to drop to 25% of its original value?

What does a 'spontaneous' process mean in the context of radioactivity?

A nucleus $X$ with mass number $A$ and atomic number $Z$ undergoes beta-plus decay to form nucleus $Y$. What are the mass number and atomic number of $Y$?

Which of the following isotopes is commonly used for carbon dating of once-living materials?

If a radioactive isotope has a very small decay constant, what can be said about its half-life?

Two nuclei undergo fusion. If the mass of the resulting nucleus is $M$ and the sum of the masses of the initial nuclei is $m$, which statement is true?

If the activity of a sample is $A$ and the number of atoms is $N$, the probability of an atom decaying per unit time is:

In the process of electron capture, a nucleus absorbs an orbital electron. Which of the following is an immediate result of this process?

Calculate the ratio of the radius of a $^{216}Po$ nucleus to the radius of a $^{27}Al$ nucleus.

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Which quark is in the same generation as the tau lepton?

Which of the following is the exchange particle for the gravitational force (hypothetically)?

The Higgs boson is primarily associated with which property of particles?

A particle with a baryon number of 0 and an electric charge of +1 could be:

Which of the following particles does NOT experience the weak interaction?

In beta decay, the emission of a neutrino (or anti-neutrino) was originally postulated to explain the conservation of which quantity?

What is the baryon number of an anti-neutron?

The $Z^0$ boson is a neutral mediator of the weak interaction. During studies at the LEP collider, $Z^0$ bosons were observed to decay into pairs of quarks. Given the vertex in the diagram below, which statement correctly identifies the requirement for the flavors of the quark ($q$) and antiquark ($q'$) produced according to the Standard Model?

A limitation of the Bohr model of the atom is that it violates the Heisenberg Uncertainty Principle. Why is this?

Which of the following is the quark composition of a negative pion ($\pi^-$)?

How many electrons can the first energy level ($n=1$) hold in a simple shell model?

Which of the following is true for the strong nuclear force?

What is the mass number of an atom with 1 proton and 0 neutrons?

Which of the following particles is not a nucleon?

An electron in an atom undergoes three possible transitions between energy levels $E_1$, $E_2$, and $E_3$, where $E_3 > E_2 > E_1$. The wavelengths of the photons emitted during these transitions are $\lambda_1$ (for the transition $E_3 \to E_2$), $\lambda_2$ (for the transition $E_2 \to E_1$), and $\lambda_3$ (for the transition $E_3 \to E_1$). Which of the following correctly expresses $\lambda_3$ in terms of $\lambda_1$ and $\lambda_2$?

An atom transitions from level $E_2$ to $E_1$. The wavelength of the emitted light is $\lambda$. If the energy difference $(E_2 - E_1)$ is doubled, the new wavelength will be:

Which of the following is correct regarding the forces within a nucleus?

The diagram illustrates the four lowest energy levels of a hypothetical atom. An electron transition from level $n=4$ to $n=3$ results in the emission of a photon with wavelength $\lambda$. A transition from level $n=3$ to $n=2$ results in the emission of a photon with wavelength $2\lambda$. Which of the following expressions represents the wavelength of the photon emitted during a transition from $n=4$ to $n=2$?

An alpha particle (charge $+2e$) is fired directly at a stationary gold nucleus (charge $+Ze$) with an initial kinetic energy $E_k$. The distance of closest approach to the gold nucleus is $r$. If the alpha particle is replaced by a different incident nucleus with a charge of $+4e$, and it is fired at the same gold nucleus with the same initial kinetic energy $E_k$, what is the new distance of closest approach?

Which of the following is a baryon?

What is the primary reason that heavy nuclei like Uranium are unstable and prone to fission?

Which isotope is 'fertile', meaning it can be converted into a fissile material (like Pu-239) in a breeder reactor?

During the fission of U-235, the sum of the masses of the resulting fragments and neutrons is:

Which of the following is a safety feature designed to stop the fission reaction quickly in an emergency?

A nuclear power plant has an efficiency of $30\%$. If the reactor produces $3000\text{ MW}$ of thermal power, what is the electrical power output?

Which of the following provides the best evidence that nuclear fission releases energy?

What is the typical kinetic energy of a neutron immediately after it is released in a fission reaction?

If $1$ kg of fuel is $3\%$ U-235 and $97\%$ U-238, and only the U-235 undergoes fission, what is the total energy available from this $1$ kg of fuel? (Assume $200$ MeV per fission).

Which of the following is a byproduct of U-235 fission that acts as a 'neutron poison' by having a very high neutron absorption cross-section?

In a nuclear accident, the 'meltdown' refers to:

Which of the following is the largest distance unit?

The 'Binding Energy per Nucleon' curve explains why:

During the fusion of Hydrogen into Helium, what particle is often emitted to conserve lepton number?

What is the Oppenheimer-Volkoff limit?

A star is 10 parsecs away. What is its parallax angle in arcseconds?

What happens to the wavelength of peak emission of a star as it cools down?

Which part of the Hertzsprung-Russell diagram contains the most stars?

The apparent brightness of a star is $B$. If the star's luminosity doubles and its distance from Earth also doubles, what is the new apparent brightness?

What is the energy equivalent of $1 \text{ atomic mass unit (u)}$ in Joules?

In the context of the HR diagram, white dwarfs are found in the bottom-left because they are: