Ph.D

Firstly, it doesn't really matter from which college you are(nor does its ranking). all you have to do is get a Be-Tech degree with 60% aggregate and clear JEST.
Now simply looking at the sample paper/syllabus will not get you through the exam. JEST covers the entire B.Sc physics syllabus and that's not a walk in the park.
books, books and more books are your only tool and so start READING.
Given below is a link from where you can get the list of recommended books for JEST
http://entrance-exam.net/syllabus-and-reference-books-for-jest-physics-exam/
My personal advice for the starting reference would be the "The Feynman Lectures on Physics." .

Application and admissions
Applications for PhD study in India should be made well in advance of the start date for your proposed programme of study. This is because the process of gaining admission to an Indian university can involve various stages and you will need to have confirmed your place on a PhD programme before you can apply for a student visa.
Admissions requirements
Indian universities are free to set their own standards for admission to PhD programmes, but most will require a similar set of application materials. These should include a research proposal, detailing the proposed outline of your PhD project, and explaining the methodology you plan to employ.
Most Indian PhD programmes will expect you to have completed a postgraduate Masters, but you may be able to apply with a good undergraduate degree if you can demonstrate sufficient experience and expertise in your proposed field. Most common international qualifications will be recognised by Indian universities. If in doubt, you can contact the Association of Indian Universities or ask for advice from your specific institution.
Examinations and interviews
India is relatively unique in requiring all prospective PhD students to sit an entrance examination before being admitted to undertake doctoral research. This is referred to as the National Eligibility Test (NET) and is administered by the University Grants Commission (UGC) for most subjects, with the exception of Science and Engineering which are covered by the Council of Scientific and Industrial Research (CSIR). As you may have noticed, Indian Higher Education is quite fond of acronyms!
In some cases, you may also be required to attend an interview at your university (this is more likely if you are applying to an Institute of National Importance). Interview procedure varies among institutions, but may involve giving a presentation on your proposed research topic. Universities may not be able to assist with travel and accommodation costs for international students attending an interview and you are advised to check in advance if this is part of the admissions process at your proposed institution.
Indian universities will usually charge an application fee, but this is nominal - often no more than ?100 ($1.5).