The particular experiments chosen depend on the interests of the instructor and students. They could include experiments from classical mechanics, thermodynamics, electromagnetism, optics, and, certainly, modern physics. Some of these experiments will let you practise the skills you learned in Electronics Instrumentation Lab, including computer interfacing. Lab reports will include advanced techniques of data analysis as well as continued emphasis on good technical writing. We'll sit here on this bench and talk about how math and computer science intertwine with the physics major.
Physics majors take lots of math because math is the language of physics.
The universe is filled with changing quantities. Many things depend on the rate at which other things change. Calculus allows you to precisely describe these changes and relationships. Three semesters of calculus are needed to master differentiation, integration, and working with quantities that depend on more than one variable. Since almost all important laws of physics are mathematically expressed as differential equations which you must solve to find the knowledge you desire, a course in differential equations is a prerequisite for upper level physics courses.