Science

Yes,
Essential Food Safety and Hygiene Practices are Compulsory for the Students of Hotel Management and every student must keep this In mind. However, Sikh students are exempted with some guidelines. Here I have provided undermentioned links of IHM Gurdaspur and Kashmir. Please go through these links to understand the dress codes. Dress codes of almost all IHMs are same with little differences:
https://www.ihmgurdaspur.org/institute-rules-and-regulation.php
http://www.ihmsrinagar.org/index.php?option=com_content&view=article&id=31&Itemid=52&showall=1
Good luck.

Yes, for the entrance exam the syllabus will be of 11th and 12th. You can refer your own book and if you to do extra you can take any other author's book for better reference.

No, the date has not been notified yet.

4 cut off lists have been out at Delhi University's website. You can go check their cutoffs under science cutoff list. You can check your course related latest cutoff according to your percentage and category.

On the last year expectations the % is 90.

You have to just wait for the 12th exams results first and then you can wait for the cutoff list by Delhi University. Delhi University takes admissions on merit basis. So you can go and check your cutoffs according to you course and percentage.
For some courses Delhi University takes entrance exam also. For information about this you can check on Delhi University's website.

Admission to all B.Sc courses in DU are done on merit based on class 12th percentage. However, there are few courses that require you to sit in an entrance examination.
So you can check cutoffs accordingly.
For more information you can check on Delhi University website or you can ask more questions from us.