I have UK student dependent Visa, in how many days i must travel to UK ?

Answer 1

If you have a UK Visa as a student dependant - and assuming that that person is still studying in the UK and is actually in the UK at the time of your arrival - then you can travel to the UK at ANY TIME during the visa's validity. You cannot lawfully stay one day beyond the validity - unless you have already applied for an extension through the Home Office.