General applications of nuclear physics refers to both applications as a result of nuclear physics and applications which employ nuclear physics. An example of the former would be medical imaging. Had there never been any sort of thing known as nuclear physics, we wouldn't need imaging techniques to scan the body for radiation. An example of an application employing nuclear physics would be radioactive dating. The radioactive properties of certain elements are used in order to determine the age of something.
Medical Imaging (such as CAT scans and MRI) is used to determine the amount of radiation a person has been exposed to. There have been quite a few different techniques and more are still being developed and improved presently.
Radioactive Dating uses radioactive properties of certain elements to determine the age of something such as an ancient person.
Radiation Detection involves different instruments used in order to detect radiation present somewhere.