Hey Swayan,

If you are having a degree of any one mentioned in your question you can apply for GATE exam. GATE is only an exam which tests your technical skills and general skills. On the basis of that PSU recruit their employees. 

To get into any of the PSU then you must have a rank below 200 and to get top 10 PSU calls then you must have below 100 ranks. Anybody can give GATE exam

Hope that helps 

all the best