Online Preliminary Examination-may,2020 For B.Sc.-VI Semester,Organized By Department Of Physics,Sgmm Hingna,Dist-naGPur

Nuclear fusion is a reaction in which two light nuclei combine to form a heavier nucleus. This process releases a large amount of energy. This is different from nuclear fission, where a heavy nucleus is split into two or more lighter nuclei. Therefore, the correct answer is "Two light nuclei of low mass to produce a heavy nucleus."

Gamma radiation is more penetrating and energetic than beta radiation and alpha radiation. Gamma radiation consists of high-energy photons that can easily pass through most materials, including thick layers of concrete and lead. Beta radiation consists of high-energy electrons or positrons, which have less penetrating power than gamma radiation and can be stopped by a few millimeters of aluminum or a few centimeters of plastic. Alpha radiation consists of helium nuclei, which have the least penetrating power and can be stopped by a sheet of paper or a few centimeters of air. Therefore, gamma radiation is the most energetic and penetrating out of the given options.

The Michelson-Morley experiment was conducted to detect the possible motion of the Earth relative to the ether. The experiment aimed to measure the change in the speed of light in different directions as the Earth moved through the hypothetical ether medium. The null result of the experiment, which showed no variation in the speed of light, led to the rejection of the concept of the ether and had significant implications for the development of Einstein's theory of relativity.

The equation E = mc2, derived by Albert Einstein, states that energy (E) is equal to mass (m) multiplied by the speed of light squared (c2). This equation shows that mass and energy are interchangeable and can be converted into one another. It implies that mass is a form of energy and vice versa, highlighting the concept of mass-energy equivalence. Therefore, the correct answer is that energy and mass are different forms of the same thing.

The cardiovascular system is responsible for supplying oxygenated blood to the body's tissues and organs and removing deoxygenated blood from them. It consists of the heart, blood vessels, and blood. The heart pumps the blood, while the blood vessels transport it throughout the body. This system plays a crucial role in maintaining the body's overall function and ensuring that all organs receive the necessary nutrients and oxygen for their proper functioning.

The correct answer is Sir Ernest Lawrence. He was an American physicist who invented the cyclotron in 1929. The cyclotron is a type of particle accelerator that uses a magnetic field to accelerate charged particles in a spiral path. Lawrence's invention revolutionized the field of nuclear physics and paved the way for further advancements in particle physics research. His work earned him the Nobel Prize in Physics in 1939.

A frame of reference with four coordinates, x, y, z, and t, is referred to as a space-time reference. This term combines the three dimensions of space (x, y, and z) with the dimension of time (t) to describe the position and motion of objects in a four-dimensional framework. It is used in the theory of relativity to understand how space and time are interconnected and how they affect the behavior of objects.

The correct answer is m = m0/sqrt(1 - v^2/c^2). This equation represents the variation of mass with velocity, known as relativistic mass. It shows that as an object's velocity approaches the speed of light (c), its mass increases. The denominator term (1 - v^2/c^2) accounts for the relativistic effects of time dilation and length contraction, ensuring that mass cannot exceed infinity. This equation is a fundamental concept in special relativity and helps explain the behavior of particles at high speeds.

The correct answer is Geiger Muller counter. This type of detector operates based on the principle that when nuclear radiations pass through a gas, it causes ionization of the gas. The Geiger Muller counter detects these ionizations and produces an electrical pulse, which can be counted and measured. This principle is used in Geiger Muller counters to detect and measure the intensity of nuclear radiations.

Uranium is used as fuel in nuclear reactors. Uranium-235 is the most commonly used isotope for nuclear fission reactions. It undergoes a process called nuclear fission, where the nucleus of the uranium atom is split into two smaller nuclei, releasing a large amount of energy. This energy is harnessed to generate electricity in nuclear power plants. Radium and plutonium are not typically used as fuel in nuclear reactors.

Ultrasonography is a medical imaging technique that uses high frequency sound waves and their echoes. These high frequency sound waves are sent into the body and when they encounter different tissues or organs, they bounce back as echoes. These echoes are then used to create images of the internal structures of the body, allowing healthcare professionals to diagnose and monitor various conditions. The high frequency of the sound waves used in ultrasonography allows for better resolution and detailed imaging of the body's structures.

The correct answer is Electroencephalogram or EEG. This is the study and analysis of signals that arise due to the electrical activity of the brain. EEG is commonly used in medical and research settings to monitor brain activity and diagnose various neurological conditions. It involves placing electrodes on the scalp to detect and record the electrical impulses produced by the brain.

The P wave in a normal ECG signifies arterial depolarization. Depolarization refers to the contraction of the heart muscle, and the P wave represents the depolarization of the atria. This electrical signal initiates the contraction of the atria, allowing them to pump blood into the ventricles. Therefore, the correct answer is arterial depolarization.

The Geiger Nuttal law states that the shorter the half-life of a radioactive isotope, the more energetic its emitted alpha particles will be. This law is based on the observation that as the half-life decreases, the probability of alpha decay increases, leading to more energetic alpha particles being emitted. Therefore, the correct answer is Geiger Nuttal law.

According to special relativity, all of the listed physical properties - time, energy, and length - are dependent on the observer's speed. This is because special relativity states that as an observer's speed approaches the speed of light, time slows down, energy increases, and length contracts. Therefore, the observer's speed has an impact on all of these properties.

The correct answer is Alpha particle. A helium nucleus consists of two protons and two neutrons, which gives it a charge of +2. It is emitted during certain types of radioactive decay, such as alpha decay. Alpha particles have a high ionizing power and can be stopped by a few centimeters of air or a sheet of paper. They are commonly used in medical and industrial applications, as well as in particle physics research.

Henri Becquerel discovered radioactivity. He accidentally discovered this phenomenon while conducting experiments with uranium salts. Becquerel noticed that a photographic plate, which he had left near the uranium salts, had been exposed without any external source of energy. This led him to conclude that uranium emits a form of radiation that can penetrate matter and affect photographic plates. This groundbreaking discovery paved the way for further research by scientists like Marie and Pierre Curie, who later expanded our understanding of radioactivity.

The biopotential at the cellular level is due to depolarization and repolarization of the cell. Depolarization refers to the change in the cell's membrane potential, where the inside of the cell becomes less negative. This change is caused by the influx of positive ions into the cell. Repolarization, on the other hand, is the process of restoring the cell's membrane potential back to its resting state. This is achieved by the efflux of positive ions from the cell. These processes of depolarization and repolarization are essential for generating electrical signals in cells, which play a crucial role in various physiological processes.

Gamma-ray photons are particles of electromagnetic radiation. They are massless because they travel at the speed of light and have no rest mass. Additionally, gamma-ray photons have no electric charge because they are not composed of charged particles. Therefore, the correct answer is that gamma-ray photons have no mass and no electric charge.

Biophysics is the branch of science that focuses on understanding the physical principles that govern biological systems. It involves the application of physics principles and techniques to study biological phenomena, such as the mechanics of cell membranes, the behavior of proteins, and the electrical properties of neurons. By studying the physical aspects of biological processes, biophysicists aim to gain a deeper understanding of how living organisms function. Therefore, the correct answer is "Physical principles involved in biology."

Nuclear fusion is the correct answer because it is the type of reaction that takes place in the sun. Nuclear fusion is the process in which two or more atomic nuclei combine to form a heavier nucleus, releasing a large amount of energy in the process. In the sun, hydrogen nuclei combine to form helium nuclei, releasing a tremendous amount of energy in the form of light and heat. This fusion reaction is what powers the sun and enables it to emit light and heat.

In a nuclear fission reaction, a heavy nucleus is fragmented into lighter ones. This process releases a large amount of energy.

Mass defect and binding energy are equivalent because they both refer to the difference in mass between a nucleus and its individual nucleons. The mass defect is the difference between the mass of a nucleus and the sum of the masses of its protons and neutrons. This mass difference is converted into binding energy, which is the energy required to hold the nucleus together. Therefore, the two concepts are interconnected and can be considered equivalent.

Neutrons are not accelerated by cyclotrons because they do not carry an electric charge. Cyclotrons work by using an alternating electric field to accelerate charged particles in a circular path. Since neutrons are electrically neutral, they do not experience a force in the electric field and therefore do not get accelerated.

During beta decay, a neutron in the nucleus of an atom is converted into a proton, and an electron (beta particle) and an antineutrino are emitted. The antineutrino is often referred to as a neutrino, as both particles are very similar in nature but have opposite charges. Therefore, the correct answer is neutrinos.