Will I have to teach other subjects apart from physics?
The short answer is: almost certainly in Key Stage 3, maybe in Key Stage 4 and in exceptional circumstances post-16.
The long answer involves looking at individual schools and individual teachers within them. It also depends on what subjects you choose to train in.
At A-level, it’s likely that you will not teach chemistry or biology. Schools are more likely to have specialist teachers in these subjects than in physics so your time will be dedicated to teaching physics.
You can now also train to teach physics with maths through university and school-based training.