I see that in cracku mocks, once the 40 mins time of a section is completed we need to manually click on submit button to start the next section.
In CAT exam is it okay if I take a half minute pause / break between sets?

No it changes automatically and pretty much instantly.

Hi Vamshi Krishna, In the final exam, you will not have the option to take a break between the sections. Each section is automatically submitted, and the next section will be started once the time allotted for each section is over. Hope this helps!

It changes automatically in the exam and you should nt be taking breaks in between sections if you want to get the real experience of giving a mock!