Dear 

Please be clear for what are you talking about that is for what thing you are asking that 'how long it takes' . You didn't mentioned any thing like for which course or college you are searching.

The basic payscale of an assistant archaeologist employed with the archaeological survey of India is between Rs.15,000 to 20,00. It depends on your skills & capability.

There are the National level exam NATA, JEE main Paper II & many state level exam also for B.Arch. admission in which you can appear.

NATA Eligibility CriteriaYou must passed/appearing in 10+2 or equivalent exam from a recognised board with Mathematics as one of the subjects (with 50% marks) are eligible to appear in NATA 2017.  

For further you can go through with given below link.

NATA Eligibility

JEE Main PaperII Eligibility:

You should have 5 subjects for B.Arch/ B.Planning are:

1-Language, 2-Physics, 3-Mathematics (compulsory), 4-Any one of (Chemistry, Biology, Biotechnology, Technical Vocational Subject), 5-Any other subject

For further you can go through with given below link.

JEE Main Eligibility

Good Luck!

Here are some of the colleges name for Archeology you can prefer.

Department of Archaeology, University of Kerala

Department of Ancient History and Archeology, University of Madras

Delhi Institute of Heritage Research and Management

Deccan College Post Graduate and Research Institute

Good Luck!

As an Archaeologist you can work in private or government-owned museums for the safe upkeep and management of museum artifacts.

In this profession of archaeology, the jobs are offered to those who have interest in knowing past of the humans, animals, or civilization that existed thousands years ago. Aspirants can find job in government sectors through exam conducted by Union Public Service Commission or Staff Selection commission.