Medicine & Health Sciences Entrance Exam

Hello Isha,
Yes, NEET is a single entrance exam to get in private colleges also, but you have to apply their application form also. Means, only one score is valid at every place but have to apply their forms.

Required score is above 520 to get into reputed colleges for gen through central counselling, but it may be 5-10 less through respective state's counselling.

If you want to do MBBS in India, clearing NEET (PMT) is necessary. If you want to do MBBS abroad then you need to have a good academic record.

NEET is the only gateway for admission into MBBS and BDS courses in India.
Find more details at the official website of CBSE NEET.
cbseneet.nic.in
All the best.

Minimum 65% percentage in general category is required to get admission in MBBS. For reserved category, this percentage is a bit low.
All the best.

The eligibility to apply is you need to clear 12th with an aggregate marks in PCB (botany + zoology) for OC – 50%, BC – 45%, MBC – 40% and SC / STY – 35%.

There is nothing such as passing marks in NEET. They are qualifying marks, i.e. 50 percentile (118 marks). For a government medical college seat you have to secure at least 530 (all India quota) in NEET. 530 is a safe score but it depends on number of rounds of counselling conducted by MCI. Cutoff may come down, but still try to secure above 510 marks.

NCERT is the best book for NEET preparation. Some of the books you can refer are:-
Physics:
Concepts of Physics by HC Verma- Vol. 1.
Concepts of Physics by HC Verma- Vol. 2.
Objective NCERT at Your Fingertips for NEET by MTG.
New Pattern Chemistry for NEET, AIPMT, JEE Main & Advanced by R.K Gupta.
Organic Chemistry Paperback by Robert Thornton Morrison.
Concise Inorganic Chemistry by JD Lee.
Trueman's Elementary Biology - Vol. 1.
Trueman's Elementary Biology - Vol. 2.
NEET Guide for Biology by MTG.

First, study NCERT books thoroughly, understand the concepts and also prefer other practice books.

No college will give you admission with this score if you are a general or OBC category student.