Radioactive decay
Tested in 3 real MPSC questions across 1 year (2020–2020). See it in context on the interactive Concept Graph →
Years it was asked
What you need to know first
Real questions that test this
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.