Question
Download Solution PDFOne-sixteenth of initial amount of radioactive substances remains undecayed after two hours. The half-life of the substance is _________.
Answer (Detailed Solution Below)
Detailed Solution
Download Solution PDFTo determine the half-life of a radioisotope is to use the fraction left undecayed as a measure of how many half-lives have passed. The mass of a radioactive isotope gets halved with the passing of every half-life, which means that
-
1 half-life→1/2 left undecayed
-
2 half-lives→1/4 left undecayed
-
3 half-lives→1/8 left undecayed
- 4 half-lives→1/16 left undecayed
Therefore, 4 half-lives must pass until you have 1/16 of the original sample. Mathematically, this means that
t / t1/2 = 4
Since 2 hours have passed i.e. 120 minutes have passed
Therefore, the half-life of the substance is
120 / t1/2 = 4 or t1/2 = 120 / 4 =30 min
Last updated on Jun 16, 2025
-> RRB JE CBT 2 answer key 2025 for June 4 exam has been released at the official website.
-> Check Your Marks via RRB JE CBT 2 Rank Calculator 2025
-> RRB JE CBT 2 admit card 2025 has been released.
-> RRB JE CBT 2 city intimation slip 2025 for June 4 exam has been released at the official website.
-> RRB JE CBT 2 Cancelled Shift Exam 2025 will be conducted on June 4, 2025 in offline mode.
-> RRB JE CBT 2 Exam Analysis 2025 is Out, Candidates analysis their exam according to Shift 1 and 2 Questions and Answers.
-> The RRB JE Notification 2024 was released for 7951 vacancies for various posts of Junior Engineer, Depot Material Superintendent, Chemical & Metallurgical Assistant, Chemical Supervisor (Research) and Metallurgical Supervisor (Research).
-> The selection process includes CBT 1, CBT 2, and Document Verification & Medical Test.
-> The candidates who will be selected will get an approximate salary range between Rs. 13,500 to Rs. 38,425.
-> Attempt RRB JE Free Current Affairs Mock Test here
-> Enhance your preparation with the RRB JE Previous Year Papers.