I am currently an undergraduate student at a department of applied mathematics. Its a 4 years (240 ects) program in which I can take lots of physics classes directly from the department of physics of my university as well. The thing is that I start to believe that I like more to do physics unfortunately I don't know if that is a viable option for me. What I mean is that I don't know if I can pursue a physics Ph.D (lets say on something relevant to theoretical physics) after my graduation. Is it mandatory to get a masters degree in physics first, in order to be accepted for a Ph.D in physics because my degree will be more relevant to mathematics? I apologize for my English its just that I am not a native speaker (also I don't study in an English speaking university ) but of course I will continue studying English with the hope to be more than proficient when I manage to get my degree because I aim to continue my academic career in USA or England. I thank you in advance for your advise.