Nuclear Physics Flashcards
What is nuclear physics?
The study of atomic nuclei, their composition, structure, and behavior.
What is an atom?
The smallest particle of an element that retains the chemical properties of that element.
Define nucleus.
Tiny, dense, central region of an atom containing most of its mass, composed of protons and neutrons.
What are electrons?
Negatively charged particles orbiting the nucleus and existing in electron shells or energy levels.
What is the charge and mass of an electron?
Charge: −1.602 × 10−19 C; Mass: 9.11 × 10−31 kg.
What is the charge and mass of a proton?
Charge: +1.602 × 10−19 C; Mass: 1.6726 × 10−27 kg.
What is the charge and mass of a neutron?
Charge: 0; Mass: 1.6749 × 10−27 kg.
What contributes to the mass of an atom?
Only the nucleus contributes to the mass of an atom (more than 99.9%).
What is the mass number (A)?
The sum of the number of protons and neutrons in the nucleus.
What is the atomic number (Z)?
The number of protons in a neutral element.
How is a neutral element designated in the periodic table?
By the notation AZX, where A is the mass number and Z is the atomic number.
What is the formula for estimating atomic radius (R)?
R = R0A1/3 = (1.2 × 10−15m)A1/3.
What is nuclear force?
The force that holds the nucleons together, overcoming the electrostatic repulsion between protons.
What determines the stability of a nucleus?
The balance between repulsive electrostatic forces between protons and attractive strong nuclear forces.
What are isotopes?
Elements having the same atomic number (Z) but different mass numbers (A).
Who discovered the nucleus of an atom?
Ernest Rutherford in 1911 through the gold foil experiment.
What were the drawbacks of Rutherford’s atomic model?
- Lack of stability
- Absence of electron energy levels
- Shell structure and subatomic particles
- Failure to explain chemical properties
- Limitations in heavy atoms.
Who discovered the electron?
J.J. Thomson in 1897.
Who discovered the proton?
Ernest Rutherford in 1919.
Who discovered the neutron?
James Chadwick in 1932.
What are the four fundamental forces of nature?
- Strong nuclear force
- Weak nuclear force
- Gravity
- Electromagnetic force.
What is the strong nuclear force?
The force that holds the nucleus of an atom together by keeping protons and neutrons bound together.
What is the weak nuclear force?
Responsible for certain types of particle decays and interactions.
What is nuclear binding energy?
The energy required to disassemble the nucleus of an atom into its individual protons and neutrons.
How is mass measured in nuclear physics?
In atomic mass units (amu or u), where 1 amu = 1.660×10−27 kg.
What is the equation for mass-energy equivalence?
E = mc^2.
What is binding energy per nucleon (BEN)?
The total binding energy of the nucleus divided by the total number of nucleons.
What is nuclear stability?
The ability of an atomic nucleus to resist undergoing spontaneous changes or decays.
What factors influence nuclear stability?
- Nucleon composition
- Magic numbers
- Binding energy per nucleon
- Nuclear shape
- Energy levels.
What is radioactivity?
The spontaneous emission of particles or radiation from the nucleus of an atom.
What are applications of radioactivity?
- Nuclear power
- Medical applications
- Carbon dating
- Industrial applications.
What is alpha decay?
The emission of alpha particles during the decay process of an unstable atom to a more stable atom.
What is beta decay?
The emission of beta particles during the decay process of an unstable atom to a more stable atom.
What types of beta decay are there?
- Beta-minus (β−) decay
- Beta-plus (β+) decay.
What is gamma decay?
The emission of gamma rays, which are a form of electromagnetic radiation.
What are the secondary radiation products of beta radiation?
X-rays
X-rays can further contribute to radiation exposure.
What type of radiation are gamma rays?
Electromagnetic radiation
Gamma rays have higher energy than X-rays.
How do gamma rays compare in penetrating power to other types of radiation?
Gamma radiation has the highest penetrating power
It requires thick shielding, such as lead or concrete, to reduce intensity.
What kind of damage can ionizing radiation cause to DNA?
DNA damage and mutations
This can lead to increased risk of cancer.
What are common symptoms of radiation sickness?
Nausea, vomiting, fatigue, hair loss, skin burns
These symptoms result from acute, high-dose exposure to ionizing radiation.
Which organs are particularly sensitive to ionizing radiation?
Bone marrow, gastrointestinal tract, reproductive organs
These organs contain rapidly dividing cells.
What is the effective dose in radiological protection?
A measure of potential health risks from ionizing radiation exposure
It considers absorbed dose and radiation weighting factors.
What unit is used to express effective dose?
Sieverts (Sv) or millisieverts (mSv)
These units represent the amount of radiation energy absorbed per unit mass of tissue.
What is the absorbed dose?
The amount of radiation energy absorbed per unit mass of tissue
Measured in gray (Gy), sievert (Sv), and rad.
At what dose can radiation become fatal?
Doses above 3 Gy (300 rad) can be fatal
Doses above 6 Gy (600 rad) are almost certainly fatal.
What is the radiation weighting factor?
A factor reflecting the biological effectiveness of different types of radiation
Alpha particles have a higher weighting factor than beta particles or gamma rays.
What is the tissue weighting factor (WT)?
The relative sensitivity of different organs to radiation-induced effects
Organs like the thyroid and bone marrow are more radiosensitive than muscle tissue.
What are some safety precautions when using radioactive sources?
Training, controlled areas, shielding, minimizing time and distance, containment, PPE, ventilation, monitoring, emergency preparedness, waste management, regulatory compliance
These measures help minimize radiation exposure and ensure safety.
What are Geiger-Muller (GM) counters?
Devices that measure and detect ionizing radiation through ionization of gas
They are portable and capable of detecting various types of radiation.
What is the half-life of a radioactive substance?
The time it takes for half of a quantity of a radioactive substance to decay
Different substances have different half-lives.
What factors can affect the half-life of a substance?
Nature of the substance, decay mechanism, stability, environmental factors, concentration, isotopic variation
These factors influence decay rates and half-lives.
What is the half-life equation?
N = N0 · e−λt
This equation describes the decay of radioactive atoms over time.
What are some uses of nuclear radiation in medicine?
X-rays, CT scans, PET scans, radiation therapy
These applications help with diagnostics and treatment of various conditions.
What is radioactive dating?
A method to determine the age of rocks and minerals based on the decay of radioactive isotopes
It relies on measuring the ratio of parent to daughter isotopes.
What is nuclear fission?
The process where the nucleus of an atom splits into smaller nuclei, releasing energy
It typically involves heavy isotopes like uranium-235.
What is the significance of potassium-argon (K-Ar) dating?
Used to date volcanic ash layers and determine the age of fossils like Lucy
K-Ar dating relies on the decay of potassium-40 to argon-40.
What is nuclear fission?
A process where a heavy nucleus splits into two smaller nuclei, releasing energy and neutrons.
What is the energy released during nuclear fission primarily in the form of?
Kinetic energy of fission fragments and emitted neutrons.
What isotope is commonly used in nuclear fission reactions?
Uranium-235 (U-235).
What happens when a U-235 nucleus absorbs a neutron?
It becomes unstable and splits into smaller nuclei, releasing energy and additional neutrons.
What is produced when Plutonium-239 (Pu-239) undergoes fission?
Smaller nuclei like xenon-144 and strontium-94, along with energy and more neutrons.
What are some applications of nuclear fission reactions?
- Nuclear power reactors
- Nuclear weapons
- Isotope production
- Neutron sources
- Radioisotope thermoelectric generators (RTGs)
- Nuclear research
What is a significant concern regarding nuclear waste?
Long-term storage due to its radioactivity lasting from decades to thousands of years.
What are the security risks associated with nuclear waste?
Potential misuse for the development of nuclear weapons.
What is nuclear fusion?
A process where light atomic nuclei combine to form a heavier nucleus, releasing a large amount of energy.
What isotopes are typically involved in nuclear fusion?
Deuterium (D) and Tritium (T).
What is one potential benefit of nuclear fusion?
It could provide a clean, abundant, and carbon-free energy source.
What process powers the Sun?
Nuclear fusion, specifically the proton-proton chain.
What is the primary fuel used in a hydrogen bomb?
Isotopes of hydrogen, specifically deuterium and tritium.
What is the ALARA principle?
A principle emphasizing minimizing radiation exposure to individuals and the environment.
What type of monitoring is conducted in nuclear facilities?
Radiation monitoring and measurement.
What is shielding in nuclear facilities?
Materials used to absorb or block radiation to reduce exposure.
What is the concept of half-life?
The time taken for half of a radioactive substance to decay.
What is the mass defect in nuclear physics?
The difference between the mass of the nucleus and the sum of the masses of its individual nucleons.
What does the binding energy of a nucleus represent?
The energy released when a nucleus is formed from its constituent particles.
Which particles are emitted during beta decay?
Electrons.
True or False: Nuclear fusion produces long-lived radioactive waste.
False.
Fill in the blank: The overall reaction for the proton-proton chain in the Sun is: _______.
4H → He-4 + 2H + 2e+ + 2νe + γ.
What is the half-life of a radioactive substance?
The time taken for half of the radioactive substance to decay
The half-life is a characteristic property of each radioactive isotope.
What is the binding energy of a nucleus?
The energy released when a nucleus is formed from its constituent particles
Binding energy is a measure of the stability of a nucleus.
What is the process called when a nucleus captures an electron and converts a proton into a neutron?
Electron capture
This process decreases the atomic number of the element.
Which unit is used to measure radiation exposure?
Sievert (Sv)
Other units include Gray (Gy) and Curie (Ci).
What is the phenomenon in which an unstable nucleus spontaneously emits radiation?
Radioactive decay
This process can involve alpha, beta, or gamma decay.
Which particle has the least penetrating power?
Alpha particles
Alpha particles can be stopped by a sheet of paper.
What is the process of combining two light nuclei to form a heavier nucleus called?
Nuclear fusion
This process powers stars, including the Sun.
What is the charge of an electron?
Negative
Electrons are subatomic particles found in the electron cloud around the nucleus.
What is the atomic number of an element?
The number of protons in the nucleus
The atomic number determines the element’s identity.
Which particle has the least mass?
Electron
Electrons are significantly lighter than protons and neutrons.
What process involves a radioactive nucleus spontaneously decaying and emitting radiation?
Radioactive decay
This is a key concept in nuclear physics.
Which type of radiation has the highest penetrating power?
Gamma rays
Gamma rays can penetrate most materials, requiring dense shielding like lead.
What unit is used to measure the activity of a radioactive sample?
Becquerel (Bq)
Curie (Ci) is another unit used for measuring radioactivity.
Which is an example of a naturally occurring radioactive isotope?
Uranium-238
Other examples include Radon-222.
Which nuclear reaction is responsible for energy production in the Sun?
Nuclear fusion
Fusion reactions combine hydrogen nuclei to form helium.
What describes the process of converting mass into energy in nuclear reactions?
Einstein’s law of relativity
This is expressed by the equation E=mc².
In a nuclear power plant, how is nuclear energy converted into electrical energy?
Nuclear fission
Fission reactions split heavy nuclei to release energy.
What is an important safety rule against hazards of nuclear radiation?
Wearing lead aprons and gloves
Personal protective equipment is essential for safety.
Which material is commonly used to shield against gamma radiation?
Lead
Lead is effective due to its high density.
What device is used to detect and measure the intensity of nuclear radiation?
Geiger-Muller counter
This device clicks or beeps in response to radiation.
Which statement about radioactive waste disposal is true?
Radioactive waste should be stored securely and isolated from the environment
Proper disposal is crucial to prevent contamination.
Which is an example of a non-ionizing radiation source?
Ultraviolet (UV) rays
Non-ionizing radiation does not have enough energy to remove tightly bound electrons.
Which government agency regulates and ensures the safe use of nuclear materials?
Nuclear Regulatory Commission (NRC)
The NRC oversees the nation’s nuclear energy industry.
What is the correct symbol for an isotope of carbon with atomic number 6 and mass number 14?
14C6
The notation typically places mass number before the chemical symbol.
The mass number of an atom is determined by the number of:
Protons and neutrons combined in the nucleus
The mass number indicates the total number of nucleons.
The radius of an atom is typically measured in:
Picometers (pm)
Atomic radii are usually in the range of picometers.
The volume of the nucleus of an atom is:
Smaller than the volume of the entire atom
The nucleus is very dense and compact.
The nuclear binding energy refers to:
The energy released when protons and neutrons combine to form a nucleus
Higher binding energy indicates a more stable nucleus.
Who is credited with the discovery of the electron?
J.J. Thomson
Thomson conducted experiments with cathode rays.
Who is credited with the discovery of the nucleus of an atom?
Ernest Rutherford
Rutherford’s gold foil experiment led to this discovery.
Who is credited with the discovery of the neutron?
James Chadwick
Chadwick confirmed the existence of neutrons in 1932.
What is the strong nuclear force responsible for?
Binding protons and neutrons together in the nucleus
This force overcomes the electrostatic repulsion between protons.
What is the weak nuclear force involved in?
Radioactive decay processes
It is responsible for beta decay.
Nuclear binding energy is defined as:
The energy released when protons and neutrons come together to form a nucleus
This energy is a measure of the stability of the nucleus.
What does the binding energy per nucleon (BEN) measure?
The average energy required to bind a nucleon in a nucleus
Higher BEN values indicate more stable nuclei.
Which nuclei is expected to have the highest binding energy per nucleon (BEN)?
Iron-56 (Fe-56)
Iron-56 is often considered the most stable nucleus.
Nuclear stability is determined by:
The ratio of protons to neutrons in the nucleus
A balanced ratio contributes to stability.
An atomic nucleus is considered stable if:
It has an equal number of protons and neutrons
This balance is crucial for stability.
Which statement is true regarding nuclear stability?
B. Nuclei with a high neutron-to-proton ratio tend to be more stable
Stability can vary based on the specific isotopes.
The stability of an atomic nucleus is influenced by:
The strong nuclear force
It plays a critical role in holding the nucleus together.
Radioactivity is the spontaneous emission of:
Radiation from the nucleus
This can include alpha, beta, or gamma radiation.
What is an application of radioactivity in medicine?
Cancer treatment
Radioactive isotopes are used in radiotherapy.
What are the three main types of radioactive decay?
Alpha, beta, and gamma
Each type of decay involves different particles and energy emissions.
Which type of radioactive decay involves the emission of a helium nucleus?
Alpha decay
Alpha particles are helium nuclei.
What are the dangers of ionizing radiation?
All of the above
This includes increased risk of cancer, genetic mutations, and tissue damage.
The effective dose is a measure of:
The biological damage caused by radiation exposure
It takes into account the type of radiation and its effect on human tissue.
What is a safety precaution when using radioactive sources?
Using appropriate shielding and personal protective equipment
Safety measures are crucial to minimizing exposure.
Which is a commonly used radiation detector?
Geiger-Muller counter
This device is widely used for detecting ionizing radiation.
What type of radiation detector can provide information about the energy of detected radiation?
Scintillation detector
Scintillation detectors use materials that emit light when exposed to radiation.
Radioactive isotopes can be used in:
All of the above
Applications include industrial, medical, and agricultural uses.
What affects the half-life of a radioactive element?
It remains constant for a given element
Half-life is a characteristic property of each isotope.
Which isotope is commonly used for radioactive dating of organic materials?
Carbon-14
Carbon-14 dating is used for determining the age of archaeological finds.
Radioactive dating is based on the principle that:
Radioactive decay is a constant process
This allows scientists to estimate the age of samples.
The age of Lucy or Dinkinesh was determined using:
Carbon-14 dating
This method is effective for dating organic remains.
The half-life of carbon-14 is approximately:
5730 years
This is the time it takes for half of a carbon-14 sample to decay.
In radioactive dating, the ratio of parent isotope to daughter isotope is used to determine:
The age of the sample
This ratio provides insight into the time elapsed since the organism’s death.
Which type of radiation is commonly used in medical imaging techniques such as X-rays?
Gamma rays
Gamma rays penetrate tissues and create images for diagnostic purposes.
The process of using radioactive isotopes to treat cancer is called:
Radiation therapy
This method targets cancerous cells while minimizing damage to surrounding healthy tissue.
The age of Lucy or Dinkinesh was estimated to be approximately:
3 million years
This estimate is based on fossil dating techniques.
Nuclear reactions involve changes in the:
Both atomic number and mass number of the nucleus
These changes affect the identity of the element.
Nuclear fission is the process of:
Splitting a heavy atomic nucleus into smaller nuclei
This reaction releases a significant amount of energy.
The release of energy in nuclear fission reactions is primarily due to the:
Conversion of mass into energy according to Einstein’s equation (E = mc2)
This principle explains the vast energy output of fission.
Nuclear fusion is the process of:
Combining small atomic nuclei to form a larger nucleus
Fusion occurs in stars, including our Sun.
The primary source of energy in the sun is:
Nuclear fusion
This process converts hydrogen into helium, releasing energy.
Nuclear fission reactions are used in:
All of the above
Applications include power generation and medical isotope production.
What is the major problem posed by nuclear waste from reactors?
Radioactive contamination of the environment
Safe disposal and management of nuclear waste are critical issues.
Nuclear fusion reactions are considered a promising source of energy because:
All of the above
Fusion produces less waste and uses abundant fuels like hydrogen.
What is the primary goal of safety measures in nuclear power plants?
Prevent nuclear accidents and minimize radiation exposure
Safety protocols are essential for protecting workers and the public.
