Is an hiv pcr test result reliable if taken 10 days and 20 hours (almost 11)after the exposure?? thank you

Very good, not 100%: Around 95% of newly infected people have positive PCR tests by 10-11 days. So your result is very reassuring, but for conclusive testing also have an antibody test (or duo test, i.e. antibody + p24 antigen) at 4 weeks. In the meantime, you can relax, especially if your exposure was not particularly high risk, e.g. unprotected anal sex with an infected or high risk male partner.