The best book to prepare for competitive exams
Basic to advanced questions
- J.B. Gupta is a great one
- V.K. also has a good book on Objective Electrical Technology. Mehta & Rohit Mehta (personally, my favorite book)
- R. K. Rajput
If your base is clear, then you can go for
- ESE (IES), Previous Year last 25 years
- Gate Previous year