Question

Match List - I shows various isotopes and List II indicates their half-lives. Match List I with List - II.

List - I	List - II
A. \(^{3}\text{H}\)	I. 60 days
B. \(^{14}\text{C}\)	II. 14.5 days
C. \(^{32}\text{P}\)	III. 5700 years
D. \(^{125}\text{I}\)	IV. 12.2 years

• A. A-I, B-III, C-IV, D-II \
• B. A-IV, B-III, C-II, D-I \
• C. A-III, B-II, C-IV, D-I \
• D. A-II, B-III, C-I, D-IV

Hint:

Carbon-14 is famous for ancient dating (thousands of years), while Phosphorus-32 decays very rapidly (around two weeks). This pairing easily unlocks the entire match question.

Answer 1

The Correct Option is B

Step 1: Concept Radioactive isotopes undergo decay unique to their nuclear structure, characterized by a specific half-life ($t_{1/2}$), which is the time required for half of the radioactive nuclei to decay.

Step 2: Meaning Matching the standard radioisotopes commonly utilized in biochemistry and biological research with their definitive experimental half-lives.

Step 3: Analysis * Tritium ($^{3}\text{H}$) has a half-life of approximately 12.2 to 12.3 years $\rightarrow$ (A-IV). * Carbon-14 ($^{14}\text{C}$), heavily utilized in radiocarbon dating, has a long half-life of about 5700 years $\rightarrow$ (B-III). * Phosphorus-32 ($^{32}\text{P}$), a high energy beta emitter used to label nucleic acids, has a short half-life of 14.3 to 14.5 days $\rightarrow$ (C-II). * Iodine-125 ($^{125}\text{I}$), commonly used in radioimmunoassays, has a half-life of around 60 days $\rightarrow$ (D-I).

Step 4: Conclusion The exact mapping is A-IV, B-III, C-II, D-I, corresponding to option B. Final Answer: (B)