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SCHOOL LECTURER (SCHOOL EDU.) 2025 2026 question with answer

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Question 4

Question Paper for Lecturer and Coach (School Edu. Dept.) - Comp. Exam-2025 (Chemistry) Rajasthan हिन्दी MCQ

Q4.⁸⁵Kr की अर्धायु 10 वर्ष है। ⁸⁵Kr के 99% विघटित होने में कितना समय लगेगा?