Sonu,
The physical tests are coducted by general physician, urologist, endocronologist etc.
General physician generally tests whether there are any physical deformities by visual examination of your private parts. Looks like some people are born with some physical deformities, he would ascertain, if there is any such thing exist.
Urologist & endocronologist basically check whether all the harmone levels are normal or not. and also would ask you if you can get erection yourself otherwise he would do PIPE test to check whether there are any erection issues. They will ask you to get semen sample and get the results from the laboratory on the semen sample. Also, they may ask you to go through NPT test basing on the results of the previous tests.
Don't be anxious, be cool, hopefully everything goes fine.
All the best.