Astrophysics is the application of the law of physics to everything that lies outside our planet. As such it is the child of other sciences nut completely dwarfs them in its scope. Astrophysics differs from other branches of physics by its difficult accessibility. A deficit of tangible and visible details must be replaced by a surplus of imagination and cross-linkages, and analyses involve many more order-of-magnitude estimates than otherwise for which precision is less significant than speed and transparency. Success in research therefore depends more critically on a handy calculus.

Particle physics research is concentrated on subatomic particles, including atomic constituents such as electrons, protons, and neutrons, produced by radioactive and scattering processes, such as photons, neutrinos, and muons, as well as a wide range of unusual particles. Dynamics of particles is also governed by quantum mechanics; they exhibit wave–particle duality, displaying particle-like behaviour under definite experimental conditions and wave-like behaviour in others. The field of particle physics developed out of nuclear physics and is typically taught in close association with nuclear physics. Nuclear physics research is concentrated on understanding the matter composed of quarks and gluons, which makes up 99% of the mass of the universe.

Applied physics is an application of the science of physics to helping human beings and solving their problems. It differs from engineering because engineers solve definite problems. Applied physicists use physics or conduct physics research to advance new technologies or resolve engineering problems. In other words, applied physics is embedded in the fundamental facts and basic concepts of the physical sciences but is concerned with the use of these scientific principles in practical devices and systems.

The word Laser is an acronym for the most significant features of laser action: light amplification by stimulated emission of radiation. Laser brought about a revolution in optical technology and spectroscopy, and had a far-reaching influence in various fields of science and technology. Laser physics is concerned with various physical aspects of the operation of lasers, such as the physics of laser gain media , the temporal evolution of light in the laser resonator, or the origins of laser noise, the sensitivity of laser resonators against thermal lensing effects or misalignment.

Geophysics is a subject of natural science dealing with the physical processes and physical properties of the Earth and its surrounding space environment, and the usage of quantitative means for their analysis. The word geophysics sometimes signifies only to the geological applications like Earth's shape, its gravitational and magnetic fields, its inner structure and composition, its dynamics and the surface appearance in plate tectonics, the generation of magmas, volcanism and rock formation. Geophysics is useful to societal requirements, such as mineral resources, extenuation of natural hazards and ecological protection. Geophysical survey statistics are used to analyse potential petroleum reservoirs and mineral deposits, trace groundwater, discovery archaeological relics, determine the thickness of glaciers and soils, and evaluate sites for environmental remediation.

Computational physics deals with the study and application of numerical analysis to solve problems in physics for which a quantitative theory already exists. Historically, computational physics was the first application of modern computers in science, and is now a subcategory of computational science. Computational physics can be seen as the evolution of the field that was once called Mathematical Physics. Such a progression has been brought about by the remarkable technological progress, especially that made over the past two decades, in the development of large scale computing facilities, and their ensuing utilization to the resolution of problems in physics which do not lend themselves to exact analytical treatments.

Biophysics is an interdisciplinary science where between biology and physics-as may be concluded by its name- and it is likewise connected to other disciplines, such as mathematics, physical chemistry, and biochemistry. Throughout the history of biophysics there have been efforts to apply the actual state of physics to understand the processes of life. Even though early thoughts were based on mechanical models, later other models including electrical, thermodynamics, and quantum mechanical were used.

Quantum theory is the theoretic basis of modern physics that explains the nature and behaviour of matter and energy on the atomic and subatomic level. The nature and performance of matter and energy at that level is sometimes referred to as quantum physics. Quantum physics is the science of things so small that quantum reality has an effect. Quantum means ‘discrete amount or portion’. One of the most surprising and (historically, at least) controversial aspects of quantum physics is that it’s impossible to determine with certainty the outcome of a single experiment on a quantum system.

Electromagnetism, science of charge and forces, and fields associated with charge. An important aspect of electromagnetism is the discipline of electricity, which is concerned with the behaviour of aggregates of charge, including the distribution of charge inside matter and the motion of charge from place to place. Electromagnetism is related to the electromagnetic force that results the attraction and repulsion of electrically charged particles. It is considered one of the fundamental forces in nature, that also comprises gravitational and nuclear forces. The force and conservation laws are only two aspects of electromagnetism.

There is significant interest currently in obtaining an understanding of the physical and chemical properties of small atomic clusters, individually because of fundamental and practical reasons. At the applied level, the continuous request for further reduction of electronic and optical devices is pushing the size of their several components to the nano-scale boundary. Also, atomic clusters can function as building blocks in the construction of new, nano-assembled materials, which may possess new properties. At the fundamental level, it is very interesting to analyse how the bulk-like properties appear from those of large clusters of increasing size, which could enhance our present understanding of solid-state physics.

Nanotechnology is an application of scientific knowledge to measure, create, pattern, manipulate, utilize or incorporate materials and components in the nanoscale. It is of wider significance that the power of nanotechnology has enabled complexity to be understood at ever smaller scales, which is helping humanity to understand the specific basis of some of the oldest and most intractable of technologies, such as those involved in food and medicine

The term plasma is referred to as the fourth state of matter. Plasma is not only most energetic but also most challenging for researchers state of matter. Applications of plasma can provide major benefits over existing methods. Often, processes can be performed that are not possible in any other manner. Plasma can provide an efficiency increase in processing methods and very often can reduce environmental impact in comparison to more conventional processes.

Condensed matter physics deals with many-body interacting systems. However, it builds on, and in turn contributes to, other fields. It requires knowledge of the fundamental force laws between atoms and molecules and the properties of small groups of these particles; it thus builds on atomic and molecular physics as well as on classical and quantum mechanics. Since it focuses on macroscopic properties rather than trajectories of individual particles, condensed matter physics requires an understanding of how things behave under different averaging processes; it builds on statistical mechanics and thermodynamics. Probably the most important unifying concept to emerge from the study of condensed matter physics is that macroscopic properties are governed by conservation laws and broken symmetries.