Physics Spl

Firstly, refer NCERT for PCM and try all the problems to get you basic concepts cleared and then go for reference books like H.C.Verma for Phy., M.L.Khanna for Maths and O.P.Tandon for chemistry. I would suggest you to join a coaching as it will assist you in preparing in a proper curriculum with weekly tests to evaluate your preparation.

You can go for M.Sc with physics. B.Sc physics has good scope in teaching in school, tuition and college.it is important in research field.

IIT preparations will help you to crack NDA provided you are able to put additional effort on general awareness.

Every ray of light bends, but for all practical purposes, the bending is negligible to have any real effect on day to day applications. Only a huge mass like the sun has enough gravitational attraction to significantly alter the path of a ray of light. So what you call normal is actually straight for practical applications.
Bending of light is used by scientists to measure the mass of huge objects. The amount of bending is directly proportional to the mass of the object causing it.

Zener Diodes have highly doped p-n junctions like a normal diode allows current flow in one direction. Unlike, a normal diode also allows a huge current to flow in the reverse direction.

Hi Raheem,
I would advice you to refer to SAT's official website for study guides, tutorial videos, sample questions, etc.
You can check the below mentioned link:
https://collegereadiness.collegeboard.org/sat/inside-the-test
https://collegereadiness.collegeboard.org/sat/inside-the-test/study-guide-students