Hello! In Jawahar Navodaya Vidyalaya Dhubri, like other JNVs, students are generally not allowed to use mobile phones in the school campus, especially in classrooms and hostels. Phones are usually restricted to emergencies or with special permission from the authorities. Regarding admission to class 11, your 10th percentage of 83% is good, but admission depends on the subject stream you choose and the availability of seats. JNVs usually start their new academic session in June or July, so you should check with the school directly for the exact date and the application or counselling process for class 11 admission.