in my birth certificate my father's name is Ashok Kumar Shukla but in my 10 and 12 marksheet it is Ashok Shukla so will there be any problem during upsc exam
As per my knowledge , it is the 10th and 12th class marksheet that matters when you apply for exams. You are asked your name, yours father's name, you DOB as per your class 10th marksheet. It is specifically mentioned in the application forms. So you don't need to worry about this. Your 10th class marksheet is the proof of your DOB and other details. You will not face any problems.
All the best