HELP

Bhai please koi batado mene ray optics abhi nhi ki h baki done h ....kya ye lecture sahi hoga ....although padhna mujhe h teacher pe doubt ni h ....but taking a सलाह please batadena yrr 17F samjhke😭😭😭😭😭 Kya ise padhke sare pyqs samjhne lagunga ...karne ko ni bolra just samjhne lagu then practice 😭😭🤔🤔