Hello!!

You need not have to prepare physics for your CAT exam.CAT exam's question will cover the topics Verbal ability,Quant(Maths),Logical Reasoning and Data interpretation.You have to have a preparation only in these areas to do well in you CAT exam.To know more about the CAT preparation and to get the list of reference books for each section,visit the below given website:

https://bschool.careers360.com/articles/cat-when-and-how-start-preparations

All the best!!