how should i get a government in Thiruvananthapuram for bsc.forensic and which are the colleges.is there is any entrance for admission

Hii!
Sorry, but your question is quite unclear. But, let me tell you that, not exactly in Thiruvananthapuram, but there are a number of good Colleges across Kerala for forensic science. Some of them are-
* Government Medical College, Thiruvananthapuram
* Amritha school of medicine
* Government medical College, Kozhikode
* University of Calicut, Malappuram
Etc.,
The admissions are taken on the basis of entrance exam scores.
Unfortunately, there are no BSc forensic science Colleges in Kerala, but only for higher studies in forensics.
Hope this helps.
Good luck!