GENERAL KNOWLEDGE

Detailed explanation-1: -Carbon-14 is unstable and undergoes radioactive decay with a half-life of about 5, 730 years (meaning that half of the material will be gone after 5, 730 years).

Detailed explanation-2: -A radioactive isotope A undergoes simultaneous decay to different nuclei as: P(4/2 = 9h) Q(t1/2 = 4.5h) Assuming that initially neither P nor Q was present, after how many hours, amount of will be just double to the amount of A remaining ? A 6.0 h Correct Answer 7.0 h.

Detailed explanation-3: -These isotopes decay within the rocks according to their half-life rates, and by selecting the appropriate minerals (those that contain potassium, for instance) and measuring the relative amounts of parent and daughter isotopes in them, the date at which the rock crystallized can be determined.

Detailed explanation-4: -Radioactive isotopes of radium, thorium, and uranium, for example, are found naturally in rocks and soil. Uranium and thorium also occur in trace amounts in water. Radon, generated by the radioactive decay of radium, is present in air.