MPSC Rajyaseva 2020 GS Paper 1 — Question 55
The correct answer with a full explanation. Practice this interactively instead →
ट्रिटियमचे अर्धआयुष्य 12.5 वर्षे असून त्याचा बीटा किरणांनी क्षय होतोय. 25 वर्षानंतर मूळ ट्रिटियमचा किती अंश अक्षय शिल्लक राहील ? / Tritium has a half-life of 12.5 years, undergoing beta decay. What fraction of original Tritium will remain undecayed after 25 years ?
1)0 (शून्य) / 0 (zero)
2)0.5 / 0.5
3)0.25 / 0.25✓ Correct
4)0.125 / 0.125
The half-life of tritium is 12.5 years. After 25 years, which is 2 half-lives ($25 / 12.5 = 2$), the remaining undecayed fraction is $(1/2)² = 1/4$ of the original amount.