15.3 Nuclear Physics

• Nuclear decay and nuclear reactions are key concepts in nuclear physics.

  True
• Match the particle with its properties:

  Proton ↔️ +1 charge, 1 amu

  Neutron ↔️ 0 charge, 1 amu
• Isotopes have the same atomic number but different mass numbers.
• Radioactive decay is the process by which unstable nuclei lose energy by emitting particles.
• Nuclear physics studies strong and weak nuclear forces
• Protons and neutrons are bound together by the strong nuclear force
• What are isotopes of an element?

  Same protons, different neutrons
• What symbol represents the atomic mass of an element?

  $\bar{m}$
• Match the type of decay with its emitted particle:

  Alpha decay ↔️ $\alpha$ particle

  Beta decay ↔️ $\beta$ particle

  Gamma decay ↔️ $\gamma$ rays
• Protons and neutrons are collectively known as nucleons
• What determines the atomic number of an element?

  Number of protons
• Isotopes have the same atomic number but different mass
• The decay constant is related to half-life by the formula $\lambda =$$\frac{\ln 2}{t_{1 / 2}}$, where t_{1 / 2}</latex> represents the half-life
• Match the conserved quantities in nuclear equations with their symbols:

  Mass Number ↔️ A

  Atomic Number ↔️ Z
• In the alpha decay of Uranium-238, both the mass number and atomic number are conserved.

  True
• What is Einstein's equation relating energy and mass defect?

  $E =$$mc^{2}$
• A chain reaction in nuclear fission is triggered by neutrons
• What happens to the nucleus of an atom during nuclear fission?

  It splits into smaller nuclei
• A controlled chain reaction is used in nuclear reactors
• What is the focus of nuclear physics as a branch of physics?

  Atomic nuclei
• What are the two types of particles found in the nucleus of an atom?

  Protons and neutrons
• What are isotopes of an element?

  Atoms with same protons, different neutrons
• Match the type of decay with its emitted particle:

  Alpha Decay ↔️ α particle

  Beta Decay ↔️ β particle

  Gamma Decay ↔️ γ rays
• Balancing nuclear equations requires conserving both mass number and atomic number
• Match the conserved quantity with its symbol:

  Mass Number ↔️ A

  Atomic Number ↔️ Z
• Steps to balance the alpha decay of Uranium-238:

  1️⃣ Write the initial nuclear equation: $_{92}^{238}U \rightarrow _{?}^{?}Th +$$_{2}^{4}He$

  2️⃣ Calculate the mass number of Thorium: $238 =$$A +$$4$

  3️⃣ Calculate the atomic number of Thorium: $92 =$$Z +$$2$

  4️⃣ Substitute the values into the equation: $_{92}^{238}U \rightarrow _{90}^{234}Th +$$_{2}^{4}He$
• Match the variable in Einstein's equation with its meaning:

  E ↔️ Energy released

  m ↔️ Mass defect

  c ↔️ Speed of light
• In a controlled nuclear reaction, neutrons are absorbed to maintain a steady release of energy.

  True
• Nuclear fusion involves the combination of light nuclei, while nuclear fission involves the splitting of heavy nuclei.

  True
• MRI and PET scans use nuclear physics principles for precise diagnostic imaging.


  True
• What is the focus of nuclear physics as compared to atomic physics?

  Structure of atomic nuclei
• What are the particles found in the nucleus called collectively?

  Nucleons
• Neutrons contribute to the stability of the nucleus.

  True
• The atomic mass of an element is the weighted average of its isotopes' masses.

  True
• Alpha decay results in a decrease of the mass number by 4.


  True
• What are the two types of particles in the nucleus of an atom?

  Protons and neutrons
• What are isotopes of an element?

  Same protons, different neutrons
• What is half-life in radioactive decay?

  Time for half nuclei to decay
• What formula is used to calculate the remaining amount of a substance after $n$ half-lives?


  $N =$$N_{0} \left(\frac{1}{2}\right)^{n}$
• In the alpha decay of Uranium-238, the balanced nuclear equation is $_{92}^{238}U \rightarrow _{90}^{234}Th +$$_{2}^{4}He$, where $_{2}^{4}He$ represents an alpha particle.