How to increase the number of news to be displayed on the dashboard?

We can’t increase or decrease the number of news to be displayed on the dashboard. By default user will be able to see only latest 3 news in the dashboard. All the news can be viewed from Manage News module.

Can the news option be customized so that only a particular department or a batch can view the news?

News module is like bulletin board in an institution. It is available for all the users in the institute. To send message to particular batch or department you can either use Messaging system of School Software Pro or Event creation in School Software Pro.