Is there any specific dress code for the entrance exam?

No, you can wear casual or formal dress whatever you like. But in some of Institutes, white shirt with formal black pant. It maybe given in instructions.

No, there is no specific dress code for the entrance exam, but it depends on the level of your exams sometimes. For Regular entrance exams, you can go casual. But, if it is on professional level, I would prefer to wear formal such as shirt. Some institutes ask you to wear particular clothes such as