If you are going for the IIT JAM Physics examination, then if you have solved the EMT, Digitial Logic Gates/Boolean Algebra, MECHANICS problem from 10+2 level books, then it would be helpful. So you can think of about 20-22 marks from this. But if you want to score good, then I would recommend you to go for Griffiths for Electrodynamics. Also you should study the Mathematical Physics, Quantum Mechanics, Solid State Physics & Analog Electronics particularly, BJT, Diodes, Oscillators etc, in order to get a good score of around 40-60 which can lead you to be an IITian.

For more information regarding IIT JAM consider the link below:

https://university.careers360.com/articles/jam-programmes

I hope this helps. Wish you a great day!