Types of Radiation
What is meant by the term 'half-life' in radioactive decay?
The time taken for either: half of a sample of radioactive material to decay into another isotope, or, the time taken for the rate of measured activity on a Geiger-counter to half.
Helium-4
What is the rearranged formula to solve for mass when you know the amount of energy and speed of light?
What is nuclear fission?
Nuclear fission is a nuclear reaction in which the nucleus of a heavy atom, such as uranium-235 or plutonium-239, splits into two or more smaller nuclei, accompanied by the release of a significant amount of energy
What element does hydrogen fuse into?
Helium
Which type of radiation is the most penetrating? Explain why.
Gamma radiation is the most penetrating type of radiation because it consists of high-energy electromagnetic waves (photons) with no mass or charge, allowing them to pass through materials with minimal interaction.
What does the mass number of an isotope represent?
The sum of the number of protons and neutrons inside the nucleus of an atom
Which three variables are used in Einstein's famous energy-mass equation and what are their units?
E=Energy (J)
m=mass (kg)
c=speed of light (m/s)
Why can a nuclear fission reaction release so much energy?
For every atom that is split, a relatively small amount of energy is released, however, their are approximately 2.5 quadrillion atoms for each kilogram of uranium, so this multiplies out to an extremely large amount of total energy released.
What are the heaviest elements able to be fused by stars?
Iron and nickel
Why is radiation harmful in large doses?
High doses of ionising radiation are harmful because they can damage or destroy cells, impair organ function, and increase the risk of cancer.
What do the majority of heavy unstable isotopes eventually decay into?
The majority of heavy unstable isotopes undergo a series of radioactive decays through alpha and beta emissions, eventually transforming into stable isotopes of lead. These decay chains conclude with lead-206, lead-207, or lead-208, depending on the specific series involved.
Where can we observe energy-mass equivalence in real-life?
Energy travelling from the Sun to Earth
Everyday chemical reactions - a tiny amount of mass is converted to energy and radiated from objects
Which elements are capable of nuclear fission?
Specific isotopes of uranium, plutonium and thorium are capable of fission.
Why might nuclear fusion be a better energy source than traditional fossil fuels?
Nuclear fusions offers the potential for an abundance of much cleaner energy than from fossil fuels. Nuclear fusion would only require hydrogen, of which the Earth is abundant in, and it would not require extensive mining operations which destroy local environments and pollute the atmosphere with greenhouse gases.
How does radiation ionise atoms?
Ionising radiation ionises atoms by transferring sufficient energy to remove tightly bound electrons from their orbital shells, thereby creating charged particles or ions.
Why are isotopes with too many or too few neutrons considered 'unstable'?
Isotopes become unstable when their neutron-to-proton ratio deviates significantly from the optimal balance, leading to an imbalance between the strong nuclear force and electrostatic repulsion. This imbalance causes the nucleus to be energetically unfavorable, prompting it to undergo radioactive decay to achieve a more stable configuration.
Why is the mass-energy equivalence principle significant in understanding nuclear reactions, such as those in the Sun?
It explains how a small amount of mass can be converted into a large amount of energy, powering stars and nuclear reactions.
How does nuclear fission differ from nuclear fusion?
Nuclear fission involves splitting heavy isotopes by firing neutrons into the nucleus. Whereas nuclear fission involves the fusion of lighter isotopes to form heavier ones. Nuclear fusion requires much more precise conditions (such as temperature and gravitational pressure) to occur, whereas nuclear fission is much more easily achievable as the radioactive sample only requires a critical mass to undergo fission.
How could a nuclear fusion reactor be kept under control on Earth?
Extremely strong magnetic fields keep all of the high temperature plasma tightly bound and preventing it from escaping. However, unlike nuclear fission, if conditions for nuclear fusion are breached, the reaction simply fizzles out, so it is a relatively safe technology.
How does alpha decay help to stabilise a radioisotope?
Alpha decay stabilises a radioisotope by reducing its atomic mass and number, thereby decreasing nuclear repulsion and energy, which helps the nucleus achieve a more stable configuration
How do radioisotopes differ from regular isotopes?
Radioisotopes differ from regular (stable) isotopes in that they have unstable nuclei due to an imbalance in the number of protons and neutrons, causing them to undergo spontaneous radioactive decay and emit radiation to achieve a more stable state. Unlike stable isotopes that have balanced nuclear compositions and do not emit radiation over time.
How might humans be able to harness to concept of energy-mass equivalence to generate electrical energy for global use?
Humans currently harness mass-energy equivalence primarily through nuclear fission, where the splitting of heavy atomic nuclei releases substantial energy, as seen in nuclear power plants. Looking ahead, nuclear fusion—combining light atomic nuclei to release energy—is being actively researched as a potential source of clean, abundant electricity, with recent advancements bringing us closer to practical implementation
Why might a country opt for nuclear fission technology when other 'cleaner' alternative technologies exist?
Countries may opt for nuclear fission technology over other 'cleaner' alternatives due to its ability to provide consistent, high-density energy, which is crucial for meeting base-load electricity demands and ensuring grid stability. Unlike intermittent renewable sources such as wind and solar, nuclear power plants operate continuously, producing large amounts of electricity regardless of weather conditions, making them a reliable complement to renewable energy sources
How are massive stars able to fuse heavier elements past the hydrogen-to-helium stage?
Massive stars can fuse elements heavier than helium due to their significantly higher core temperatures and pressures compared to smaller stars. Once hydrogen fusion ceases, if the star is massive enough, it's gravitational field contracts the core, increasing the temperature until next round of fusion can commence. These stars undergo successive fusion stages, forming elements like carbon, oxygen, and eventually iron, in a layered structure resembling an onion