Question Paper for Lecturer and Coach (School Edu. Dept.) - Comp. Exam-2025 (Chemistry) Rajasthan English MCQ Q4.The half-life period of ⁸⁵Kr is 10 years. How much time will it take for 99% of the ⁸⁵Kr to disintegrate? A33.2 years B66.4 years C132.8 years D99.6 years EQuestion not attempted Show answer Correct answer: 66.4 years