i have a problem that i am not able to remember the theory part for much time.

then i am not able to apply the theory in questions.

dear,daljeet.It happens if you are studing a lot or if you are not giving tourself enough time that u need.If you are'nt studying a lot then try to work hard as much as possible.read the theory part again and again untill u get the confidence.then go for numerical problems.and do numerical problems as much as possible. I hope it will solve your problem.