The amount of time a student spends on specific RA duties depends on the amount of course work necessary and on the requirements of the specific group in which he or she is working. For new graduate students taking classes and preparing for the general examination, research duties normally require 20 hours per week or less. After two to three years, research becomes full time and generally leads to a thesis topic. TAs are graduate students who assist with teaching-related activities. TA duties may include teaching recitation sections, assisting faculty members in grading, or supervising an undergraduate laboratory.
Many students find that teaching provides invaluable experience in career preparation.
A graduate student in physics may be a TA at any point of his or her study, but the number of TA positions are limited. TA appointments cover only the nine months of the academic year. These appointments involve teaching sections in a course or lab, tutoring, or grading homework and exams. This work is done in addition to any research or class work the student is doing and requires up to about 20 hours per week. TAs are given preferentially to incoming students, although some TAs are assigned to advanced graduate students with good teaching skills.