Hello Ujjawal,

Please refer this for detailed link:

https://engineering.careers360.com/articles/psu-recruitment-through-gate

From this you can get clear idea about eligibility criteria,name of companies that come under psu,earlier year cut off,your chances and etc.

Hope I cleared your doubt.All the best for future endeavour!!!

Yes,  you can get jobs in PSUs through gate score after your graduation, but you have to apply in PSUs after your gate exam result, you have to clear a particular interview of PSUs.

All the best for your bright future.