Match List I with List II and select the correct answer using the code given below the Lists: List I (Isotope) A. Carbon B. Cobalt C. Iodine D. Uranium List II (Application) 1. Treatment of goiter 2. Calculation of age of the earth 3. Treatment of cancer 4. Fuel in nuclear reactors Code: A B C D

The correct matching of isotopes to their applications is as follows: Carbon-14 is used for radiocarbon dating to determine the age of organic materials and geological samples [3]. Cobalt-60 is a widely used radioisotope in radiotherapy for the treatment of cancer due to its high-energy gamma radiation. Iodine-131 is specifically utilized in medical applications for the diagnosis and treatment of thyroid disorders, including goiter and hyperthyroidism, because the thyroid gland naturally concentrates iodine. Uranium-235 serves as the primary fissile fuel in nuclear reactors to generate power [2]. While Carbon-14 dating is typically used for organic matter up to 60,000 years, the broader application of radioactive decay (including uranium-lead dating) is used for calculating the age of the Earth [1]. Thus, the sequence A-2, B-3, C-1, D-4 corresponds to Option 1.

Sources

1. [3] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 4: Earths Interior > Radioactive Decay > p. 58
2. [2] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 29: Environment Issues and Health Effects > 2g.t.2.Iodine - r+ > p. 413
3. [1] https://www.sciencedirect.com/topics/pharmacology-toxicology-and-pharmaceutical-science/iodine-129