Matching Physics Concepts and Applications

This question asks us to match items from List-I, which represent specific physical entities or processes, with their corresponding descriptions or applications found in List-II. Let's analyze each item in List-I and find its most appropriate match in List-II.

Analysis of List-I and List-II Pairings

• (A) Low mass number nuclei: Nuclei with low mass numbers, such as isotopes of hydrogen (deuterium and tritium), are known to be involved in nuclear fusion reactions. Fusion is a process where light nuclei combine to form a heavier nucleus, releasing a large amount of energy. List-II option (IV) is "Fusion". Therefore, (A) matches (IV).
• (B) Electron microscope: An electron microscope uses a beam of electrons to create an image of a sample. The electrons interact with the sample and are diffracted, scattered, or transmitted, and these resulting electrons are used to form the image. List-II option (III) is "Diffracted electron". Thus, (B) matches (III).
• (C) Beta decay: Beta decay is a type of radioactive decay where a nucleus emits a beta particle (either an electron or a positron). Beta particles are electrons or positrons with moderate energy. They have a medium penetrating power compared to alpha particles (low penetrating power) and gamma rays (high penetrating power). List-II option (I) is "Medium penetrating power". Hence, (C) matches (I).
• (D) $^{235}_{\;92}$U: $^{235}_{\;92}$U represents the uranium-235 isotope. This isotope is fissile, meaning it can undergo nuclear fission when bombarded by a neutron. This property makes it an essential fuel material used in nuclear reactors to generate power. List-II option (II) is "Nuclear reactor". Consequently, (D) matches (II).

Summary of Matches

Based on the analysis, the correct pairings are:

• (A) Low mass number nuclei $\rightarrow$ (IV) Fusion
• (B) Electron microscope $\rightarrow$ (III) Diffracted electron
• (C) Beta decay $\rightarrow$ (I) Medium penetrating power
• (D) $^{235}_{\;92}$U $\rightarrow$ (II) Nuclear reactor

Comparing these pairings with the given options, we find the combination (A)-(IV), (B)-(III), (C)-(I), (D)-(II).

Revision Table: Key Concepts Review

Additional Information: Exploring Physics Phenomena

Let's delve a bit deeper into the concepts involved in this matching question:

• Nuclear Fusion: This process powers the sun and stars. It requires extremely high temperatures and pressures to overcome the electrostatic repulsion between positively charged nuclei. Research is ongoing to achieve controlled nuclear fusion on Earth as a potential clean energy source. Deuterium ($^{2}_{\;1}$H) and Tritium ($^{3}_{\;1}$H) are common reactants in fusion experiments.
• Electron Microscope: Unlike light microscopes that use photons, electron microscopes use electrons. Due to the wave nature of electrons (de Broglie hypothesis), they have a much shorter wavelength than visible light. This allows electron microscopes to achieve significantly higher resolution, enabling visualization of structures at the nanoscale, such as viruses or atomic arrangements.
• Beta Decay: This is one of the primary types of radioactive decay, along with alpha decay and gamma decay. In beta-minus decay, a neutron in the nucleus converts into a proton, emitting an electron (beta particle) and an antineutrino. In beta-plus decay, a proton converts into a neutron, emitting a positron (beta particle) and a neutrino. The penetrating power refers to how far the radiation can travel through matter.
• Nuclear Reactor: This is a device used to initiate and control a self-sustained nuclear chain reaction, usually involving nuclear fission. The energy released from the fission of heavy nuclei like $^{235}_{\;92}$U or $^{239}_{\;94}$Pu is used to generate heat, which can then be converted into electricity. Control rods are used to absorb neutrons and regulate the reaction rate.