Physics is the study of the physical world and the rules that apply to it. There are many tiny particles at the nuclear level. A nuclear physicist studies the way these interact with each other, and how the characteristics of the nuclear world can be applied to engineering and human endeavors. Various subspecialties make up the field of nuclear physics, which include theoretical work, experimental examination of nuclear particles, and designing equipment.

The nuclear aspect to physics concentrates on the components of the physical world that include atoms, neutrons and protons. Many countries use nuclear engineering, based on an understanding of nuclear physics, to produce energy through nuclear power. Apart from the industrial applications of nuclear physics, the study of this type of physics elucidates knowledge about how the natural world works.

Academic jobs are one subsection of nuclear physicist jobs. Commonly, a nuclear physicist employed by a university performs research and also teaches students who are studying undergraduate and postgraduate nuclear physics. Research may be theoretical, or it may be applied, and normally, an academic physicist publishes studies in academic journals so other physicists can read about it. Theoretical research involves calculations and the development of mathematical equations to represent the actions of the physical nuclear world, and for this, a nuclear physicist commonly uses computer programs. He or she may also spend time developing computer programs for this purpose.

In private enterprise, a nuclear physicist may have a job as a researcher, working directly in conjunction with nuclear engineers to produce new forms of equipment, and new techniques for systems such as nuclear energy plants. Public service roles may also involve this type of work, as well as work in the military field in weapons inspections or development. Regulatory bodies can employ nuclear physicists as researchers or as experts to develop rules for safe levels of nuclear exposure. They may also be involved in testing the radioactivity of specific industries, or auditing the safety procedures of an industry. A nuclear physicist's day may involve regular hours, or if he or she is performing research or development, the work may require unusual hours.

Those physicists who move into supervisory roles may not perform as much hands-on research or development as previously. These roles instead require a supervisor to manage projects, envision directions for the team to go in, and organize budgets and funding. As most positions in nuclear physics require a doctoral degree, a person with a bachelor's degree typically has a career as a research assistant, or a technician servicing and maintaining the equipment.