Question

Area of nuclear cross section is measured in 'Barn'. It is equal to: (a) \(10^{-28} \mathrm{~m}^{2}\) (b) \(10^{-18} \mathrm{~m}^{2}\) (c) \(10^{-8} \mathrm{~m}^{2}\) (d) \(10^{-34} \mathrm{~m}^{2}\)

Short answer

The area of a nuclear cross section in 'barn' is \(10^{-28} \mathrm{~m}^{2}\), which is option (a).

Step-by-step solution

Understand the Unit

A 'barn' is a unit of area commonly used in nuclear physics to measure the cross-sectional area presented by nuclei for scattering particles like neutrons. It is defined as a specific size standard for nuclear reactions.

Recall the Definition of a Barn

The standard definition of a barn is that it is equal to \(10^{-28} \text{ m}^2\). This value is used because typical nuclear interactions have cross-sectional areas of this magnitude.

Match the Definition to Options

Compare the provided options to the defined standard of a barn, which is \(10^{-28} \text{ m}^2\).

Select the Correct Option

From the options given:- (a) \(10^{-28} \text{ m}^2\)- (b) \(10^{-18} \text{ m}^2\)- (c) \(10^{-8} \text{ m}^2\)- (d) \(10^{-34} \text{ m}^2\)The correct answer that matches the definition is option (a) \(10^{-28} \text{ m}^2\).

Key concepts

Barn Unit

In nuclear physics, the barn unit is a specific measure of area used for quantifying the likelihood of interactions between nuclear particles. Imagine the barn as an extremely tiny target for particles zooming around in nuclear reactors or experiments. It's defined as exactly \(10^{-28} \text{ m}^2\), a size that may seem minuscule, but is practical for the scale of nuclear phenomena. When we speak of interactions like neutron scattering, the barn is an essential unit. It simplifies calculations by providing a standard size reference for understanding nuclear interactions. This unit is largely applied due to its convenience in approximating typical cross-sectional areas involved in nuclear reactions. Remember, the barn's purpose is like a scale for measuring the probability of a reaction, embedded in the fabric of experiments and calculations.

Nuclear Cross Section

Understanding the nuclear cross section is vital in grasping how particles interact when they collide. A cross section in nuclear physics is essentially an area that quantifies the probability of scattering or reactions occurring as particles like neutrons move. It provides a way to predict how likely it is for particles to interact under certain conditions. The nuclear cross section is the area that represents the effective size for collision processes, directly influencing how frequently reactions occur. This is similar to how a larger physical target would have a higher chance of being hit by a projectile. It's important to note that cross sections aren’t constant values; they depend on the energy of the particles involved and the specific type of interaction. This adaptability is what makes the concept so rich and widely used in nuclear science.

Scattering Particles

Scattering is a central concept in understanding nuclear interactions. When particles like neutrons or protons come close, they can either pass by unperturbed or interact, altering their course. This deflection is known as scattering and is crucial in nuclear experiments and technology. When particles scatter, they provide insights into the structure of atomic nuclei, the forces involved, and how particles behave under varying conditions. Scattering experiments are foundational in nuclear physics because they reveal much about the size and shape of nuclei and how energy is transferred in collisions. Scattering isn’t just random; it follows specific patterns depending on the type of forces encountered and the energy levels of the particles. By studying these patterns, scientists can infer much about the internal structure and dynamics of matter at the smallest scales.

Nuclear Reactions

Nuclear reactions occur when nuclei collide and result in new elements or nuclear configurations. These reactions are fundamental to energy production in stars, nuclear power plants, and in the development of nuclear technology. There are different types of nuclear reactions, including fission, fusion, and radioactive decay. Fission involves a nucleus splitting into smaller parts, releasing vast amounts of energy—a process utilized in nuclear power plants. Fusion, the process that powers the sun, involves light nuclei combining under high pressure and temperature to form heavier elements. Understanding nuclear reactions is crucial because they hold potential for both constructive purposes like energy generation and for destructive purposes such as in nuclear weapons. Each reaction involves shifts in the atomic structure and energy levels, dictating much of the behavior we observe in nuclear physics.