(4.) Physics Hl/Sl. Atomic And Nuclear Physics / Energy, Power, Climate Change

Fuels that have been produced from the accumulations of dead matter are known as fossil fuels. Fossil fuels are formed over millions of years from the remains of plants and animals that lived long ago. These fuels include coal, oil, and natural gas, and they are non-renewable resources. Fossil fuels are widely used for energy production, but their extraction and burning contribute to environmental issues such as air pollution and climate change.

Wien's displacement law states that the wavelength at which the intensity of radiation emitted by a black body is at its maximum is inversely proportional to the temperature of the black body. In other words, as the temperature of a black body increases, the peak wavelength of the radiation it emits shifts towards shorter wavelengths (higher energy). This relationship between temperature and peak wavelength is a fundamental principle in understanding the behavior of black bodies and plays a crucial role in various fields such as astrophysics and thermal radiation.

The concept defined above is "albedo." Albedo refers to the fraction of radiation received by a planet that is reflected back into space. It is a measure of how reflective a planet's surface is.

The term being defined is nucleon. A nucleon refers to the components of a nucleus, which are protons and neutrons. Protons have a positive charge, while neutrons have no charge. Together, they make up the majority of the mass of an atom.

The given definition is describing the concept of binding energy. Binding energy refers to the amount of energy that is released when a nucleus is formed by bringing together its constituent nucleons (protons and neutrons). It represents the strength of the nuclear force that holds the nucleons together within the nucleus.

Greenhouse gases are the gases in the atmosphere that have the ability to absorb and emit infrared radiation. This process, known as the greenhouse effect, is responsible for trapping heat in the Earth's atmosphere and regulating the planet's temperature. Examples of greenhouse gases include carbon dioxide (CO2), methane (CH4), and water vapor (H2O). These gases play a crucial role in maintaining Earth's climate and are responsible for the warming of the planet.

An absorption spectrum refers to a spectrum where specific frequencies of light emitted by an element are missing or absorbed. This occurs when the element absorbs certain wavelengths of light, resulting in dark lines or gaps in the spectrum. These dark lines correspond to the specific energies needed to excite electrons in the element's atoms. By studying the absorption spectrum, scientists can identify the element and gain insights into its composition and properties.

An active solar heater is designed to capture thermal energy or heat energy from the sun in order to heat water. This means that the device is specifically engineered to maximize the amount of heat it can collect from the sun and convert it into usable energy for heating water. Therefore, the correct answer options are thermal energy, heat energy, and heat.

An artificial reaction in which a nucleus is bombarded with a nucleon, an alpha particle, or another small nucleus is known as transmutation. Transmutation refers to the process of changing one element into another by altering the number of protons in the nucleus. This can be achieved by bombarding the nucleus with particles, causing it to undergo nuclear reactions and resulting in the formation of a different element. Transmutation has been used in various applications, including the production of radioactive isotopes for medical and industrial purposes.

The critical mass is the stage in a nuclear reaction where a chain reaction can occur. In a chain reaction, the fission of one atomic nucleus releases neutrons that can go on to collide with other atomic nuclei, causing them to undergo fission as well. This process continues in a self-sustaining manner, releasing a large amount of energy. The critical mass is the minimum amount of fissile material required to sustain a chain reaction. Below this threshold, the reaction will not propagate, while above it, the reaction will continue and potentially lead to a nuclear explosion.

Do not mix up with "specific heat capacity"!

The statement is true because the half-life of a substance refers to the time it takes for half of the radioactive atoms in a sample to decay. This means that after one half-life, half of the atoms will have decayed and after two half-lives, three-fourths of the atoms will have decayed, and so on. Therefore, the definition provided accurately describes the concept of half-life.

A source of energy that cannot be used up is said to be renewable. This means that it is naturally replenished and can be continuously harnessed without depleting its resources. Renewable energy sources include solar power, wind power, hydroelectric power, and geothermal energy. These sources of energy are considered sustainable and have a minimal impact on the environment compared to non-renewable sources such as fossil fuels.

The coefficient of volume expansion measures the fractional change in volume for a given change in temperature. It quantifies how much a substance expands or contracts when its temperature changes. This coefficient is used to calculate the change in volume of a substance due to temperature variations, such as in thermal expansion calculations.

Isotopes are nuclides that have the same number of protons (atomic number) but different numbers of neutrons. This means that they have the same number of positive charges in the nucleus but different masses. The different number of neutrons gives each isotope a different atomic mass.

The statement is true because the emission spectrum of an element refers to the specific wavelengths of light that it emits when it undergoes a transition from a higher energy state to a lower energy state. Each element has a unique emission spectrum, which can be used to identify and analyze its chemical composition. Therefore, the light emitted by an element can indeed be defined as its emission spectrum.

A heat exchanger is a device that allows nuclear reactions to occur in a sealed environment, separate from the rest of the surroundings. It is designed to transfer heat from one fluid to another without mixing them, ensuring that the nuclear reactions can take place safely and efficiently. The heat exchanger facilitates the transfer of thermal energy, allowing the controlled release or absorption of heat in a controlled environment.

The given statement defines feedback as the result of a change in a process leading to a further change in one of the constants involved. This means that feedback occurs when the outcome of a change in a system influences future changes in that system. Therefore, the statement is true.

Nuclear fusion is being defined. Nuclear fission is a “nuclear reaction whereby large nuclei are induced to break up into smaller nuclei and release energy in the process”

Thermal equilibrium refers to a state in which two systems have the same temperature. This means that there is no net transfer of heat between the systems, and they are in a state of balance. In thermal equilibrium, the systems have reached a point where their temperatures are equal, resulting in a stable and balanced condition.

Radioactive decay refers to the process in which atomic nuclei undergo spontaneous disintegration, resulting in the emission of radiation. It is a natural process that occurs in unstable atoms, causing them to transform into different elements. During radioactive decay, the atomic nucleus releases energy in the form of alpha particles, beta particles, or gamma rays, leading to a decrease in the mass and atomic number of the nucleus. This process is essential in various fields such as medicine, energy production, and understanding the age of rocks and fossils.

A continuous spectrum refers to a spectrum where all possible frequencies of light are present. This means that there is a seamless range of colors without any gaps or missing frequencies. It is different from an emission spectrum, which only shows specific wavelengths emitted by a light source, and an absorption spectrum, which shows specific wavelengths absorbed by a material.

A fast breeder reactor is a type of reactor design that uses plutonium-239 as a fuel. This type of reactor is capable of producing more fissile material than it consumes, making it an efficient way to generate nuclear energy. Plutonium-239 is a highly radioactive isotope that can undergo fission and release a large amount of energy. Therefore, it is correct to say that a reactor design that utilizes plutonium-239 is known as a fast breeder reactor.

Degraded energy refers to energy that has been converted into a form that is no longer available to perform useful work. This means that the energy has been transformed into a less useful or lower-quality form, such as waste heat or dispersal of energy. It cannot be easily harnessed or utilized to perform useful tasks.

The enhanced greenhouse effect refers to an increase in the natural greenhouse effect caused by human activities. Human activities, such as burning fossil fuels and deforestation, release large amounts of greenhouse gases into the atmosphere. These gases, including carbon dioxide, trap more heat from the sun, leading to an intensified greenhouse effect and ultimately contributing to global warming. It is important to mention the enhanced greenhouse effect when discussing greenhouse gases and global warming because it highlights the role of human activities in exacerbating the issue.

Emissivity is being defined. Emissivity is a measure of how efficiently an object radiates heat compared to a black body at the same temperature. It is the ratio of the power radiated per unit area by an object to the power radiated per unit area by a black body at the same temperature.

The given definition is describing "Energy density," which refers to the amount of energy released per unit mass of fuel consumed. It is a measure of how much energy can be obtained from a given amount of fuel.

A photovoltaic cell is a device that converts a portion of the sun's radiated energy directly into a potential difference. It is commonly known as a solar cell and is used to generate electricity from sunlight.

A nuclide is being defined in this question. A nuclide refers to a particular species of atom that has a specific number of protons and neutrons in its nucleus. This term is used to describe atoms with specific combinations of protons and neutrons, which determines their identity and properties.

The given law states that the intensity of received radiation is inversely proportional to the square of the distance from the point source to the receiver. This law is known as the inverse square law. According to this law, as the distance between the point source and the receiver increases, the intensity of the radiation decreases rapidly. This law is commonly applied in various fields such as physics, astronomy, and photography to understand the behavior of radiation.

Control rods are being defined. A moderator is a material whose atoms slow down neutrons to make them suitable for reaction.

"The radiation from a perfect emitter" is correct