Test: Atomic and Nuclear Physics - SSC CGL MCQ

Atoms are composed of three primary particles: electrons, protons, and neutrons. Electrons are negatively charged particles that orbit the nucleus of an atom. Protons carry a positive charge and are located in the nucleus. Neutrons are neutral particles found in the nucleus along with protons. Understanding the structure of an atom is crucial in comprehending the behavior of matter at the atomic level.

Protons are the subatomic particles that carry all the chemical and physical properties of matter. They are located in the nucleus of an atom and determine the element's identity by their atomic number. The number of protons in an atom defines its chemical properties, making it a fundamental aspect of atomic structure.

The nucleus of an atom consists of protons and neutrons. Protons provide a positive charge, while protons and neutrons combined provide the entire mass to a nucleus. This essential understanding of the composition of the nucleus is crucial in comprehending the structure of atoms and the behavior of matter at the atomic level.

James Chadwick is credited with the discovery of the neutron. He made this significant breakthrough when bombarding beryllium with alpha particles. Neutrons play a vital role in the stability and structure of atomic nuclei, as they help balance the positive charge of protons and contribute to the overall mass of the nucleus.

When an α-particle is emitted by a nucleus, it signifies α-decay. This process involves the atomic number decreasing by 2 and the mass number decreasing by 4. α-decay is a common type of radioactive decay in nature and plays a significant role in the transformation of atomic nuclei.

The rate of disintegration of radioactive atoms at any instant, as per the Radioactive Decay Law, is directly proportional to the number of radioactive atoms present in the sample at that specific moment. This fundamental principle helps in understanding how radioactive substances decay over time, providing insights into their behavior and characteristics.

In radioactivity, the term "half-life" refers to the time it takes for half of the initially present radioactive atoms in a sample to decay. This concept is crucial in understanding the decay process and the stability of radioactive elements.

The relation between the average life (τ) and the decay constant (λ) of a radioactive element is given by τ = 1.44/λ. The average life represents the total lifetime of all atoms in a sample divided by the total number of atoms initially present, providing insights into the stability and decay behavior of radioactive elements.

Nuclear fusion is the process where two lighter nuclei combine to form a heavier nucleus, releasing a significant amount of energy. This process is the fundamental energy source of the sun and is utilized in hydrogen bombs due to its destructive power.

Somatic effects of radiation refer to those that impact the individual directly exposed, affecting their health or well-being. These effects can vary in severity but are not passed down to future generations, unlike genetic effects which alter the genetic material and can be inherited.

Electromagnetic waves are transverse waves with perpendicular electric and magnetic field vectors. This means that the electric field vector oscillates perpendicular to the magnetic field vector and to the direction of wave propagation. This unique characteristic of electromagnetic waves plays a crucial role in various applications across different fields.

The speed of electromagnetic waves in free space is determined by both the permittivity and permeability of free space. These fundamental constants play a significant role in defining the speed at which electromagnetic waves propagate through a vacuum. It's essential to understand the interplay between these properties to comprehend the behavior of electromagnetic waves in different mediums.

"Radar" stands for Radio Detection and Ranging. It operates by emitting continuous or pulsed radio waves towards an object and then detecting the waves reflected back. This technology is widely used in various applications such as tracking aircraft, ships, and missiles. Radar plays a crucial role in navigation, weather forecasting, and military operations, showcasing its versatility and significance in modern technology.

A Maser, which stands for Microwave Amplification by Stimulated Emission of Radiation, is primarily used to accurately determine the position of artificial satellites and other objects in space. Similar to lasers, masers generate a strong source of coherent microwave radiation through a process called stimulated emission. This technology finds applications in satellite communication, precision measurement, and scientific research due to its ability to produce intense and focused microwave beams.

The atomic structure plays a vital role in elucidating the interactions between matter and energy. Understanding how atoms are composed of electrons, protons, and neutrons helps in explaining various phenomena, such as chemical reactions and the behavior of substances under different conditions. By studying atomic structure, scientists can delve into the intricate relationship between matter and energy, leading to advancements in fields like chemistry, physics, and material science.