Chapter 14 1. Radio galaxies have sources of unusually strong radio waves emitted on either side of the galaxy and active galaxies are spirals with small, highly luminous cores like Seyfert galaxies, they also have nuclei that are produced by matter plunging into super-massive black holes. 6. By observing the velocity of the stars that orbit the black hole or by the rotational speed of its accretion disk. 10.
INTRODUCTION TO NUCLEAR REACTION: The main features of nuclear reactions include radioactive decay, nuclear fission and nuclear fusion. Radioactive decay: Energy is released in a radioactive decay in the form of the kinetic energy of the particle emitted (α and β), the kinetic energy of the daughter nucleus and the energy of the gamma-ray photon that may accompany the decay. The energy involved may be calculated by finding the mass defect of the reaction. The energy released is the energy equivalent of the mass defect of the reaction. Nuclear fission: Nuclear fission is the process in which a large nucleus breaks into two smaller nuclei that are almost equal in mass.
The arrangement of particles in an atom Protons and neutrons make up the main, dense, central nucleus in the centre of the atom. This is surrounded by electrons “orbiting” the main nucleus. The electron are in shells depending on their energy levels, as the most energetic are on the outer shells, because they need more energy to travel around a bigger “orbit” of the nucleus. These shells are full when a certain amount of atoms are in the shell; 2 in the first shell, 8 in the next shell, 8 in the third shell and so on. When the shells are full, the atom is unreactive.
Electromagnetic Waves in Technology Electromagnetic waves are very present in today’s society and play an important aspect in our technology. They come in many different wavelengths; there are radio, X-rays, microwave, ultraviolet, infrared, visible rays and gamma rays. One of the technologies used in medicine that requires electromagnetic waves are X-Rays. It was invented in 1895, apparently completely by accident, by a German physicist named Wilhelm Röetgen. He was experimenting with electron beams in a gas discharge tube when he noticed that a fluorescent screen in his lab began to glow when the electron beam was turned on.
Also, for every force, there is an equal and opposite force acting against it. With the exception of gravity, the electromagnetic force is the force responsible for practically all the encounters in daily life above the nuclear scale. Roughly speaking, all the forces involved in interactions between atoms can be explained by the electromagnetic force acting on the electrically charged atomic nuclei and electrons inside and around the atoms, together with how these particles carry momentum by their movement. This includes the forces we experience in pushing or pulling ordinary material objects, which come from the intermolecular forces between the individual molecules in our bodies and those in the objects. With the exception of gravity, electromagnetic phenomena as described by quantum electrodynamics account for almost all physical phenomena observable to the human senses, including light and other electromagnetic radiation, all of chemistry, most of mechanics (excepting gravitation), and, of course, magnetism and electricity.
Also, they are able to visualize the arrangement of atoms in space by using contemporary imaging instruments. The microscopes reveal many secrets of the nature, and the invention of the microscope caused to emergence of new aspects in science, such as discovering of microorganisms, studying of the animal and plant cell structure, and using in laboratory diagnosis of diseases around the world. Currently, we use several specific kinds of microscopes, such as scanning and transmission electrons, laser, fluorescent, and x-ray microscopes, in the different fields of sciences. However the evolution of microscopes depended on discovering three previous inventions that are considered precursors of compound microscopes: the creating of early simple microscope, increasing the magnification of the microscope, and solving the problem of chromatic effect. First of all, in 1284, the development of the first lens happened in Florence when an Italian glass maker Salvino D’Amati designed small convex disks from glass, and this led to the invention of the first glasses (Johnson, 2014).
At the very start, the entire universe was about a size of an atom. It was termed by Georges Lemaitre as the “primordial atom”. As one of the pioneers of in the make of the big bang theory, Georges Lemaitre proposed this new theory. At that time, this theory has explained many difficulties that were met by the theories proposed previously. For example, a theory states that the universe is infinitely large with an infinitely amount of stars was met by the Olber’s paradox.
What is the ‘Big Bang’ theory? What evidence does this theory rest upon and what do you see as the most significant problems facing the Big Bang theory? The Big Bang theory is one of the most widely acclaimed origin stories; however, it continues to face significant problems and brings up questionable implications. The theory states that an inconceivably atom-sized shape appeared and “as it appeared, it began to create space, time, matter, and energy”. Phase changes began as this shape began to expand and cool, resulting in the formation of different types of energy: gravity, electromagnetism, and the ‘strong’ and ‘weak’ nuclear forces.
Nuclear Power is produced by controlled (non-explosive) reactors. They convert the thermal energy released from nuclear fission. When uranium and plutonium are enriched, it undergoes nuclear fission. It releases kinetic energy and gamma radiation. This whole process is called a nuclear chain reaction.
“Nuclear fission is the process of breaking up atoms; the process will generate an enormous amount of energy in form of heat” (Nuclear Power and the Environment). The first man-made reactor was built in the USA in December 2, 1942 called-