Question

4. What is produced by the radioactive decay of isotopes in the mantle and crust?
A. radiogenic heat
B. primordial heat
C. superheating
D. heat from the sun​

Answer 1

Answer:

Option A

Radiogenic heat

Answer 2

Answer:

Radiogenic heat is produced by the radioactive decay of isotpes in the mantle and crust.

Explanation:

Radiogenic heat : It is the heat generated due to the decay of radioactive substances present in the crust and the mantle of the earth. Radioactive substances have unstable nuclei and they produce radioactive rays such as alpha, beta and gamma rays. They emit a huge amount of energy.

 Major radioactive substances present in crust and mantle are uranium, thorium, potassium etc. Some substances have long half life time while others have short half life time.