An aluminum foil is placed across a beam of radiation from a radioactive source. Which of the following types of radiation will be stopped by it?

Answer Details

An aluminum foil is not thick enough to stop alpha and beta particles as they have high energy and mass, and can penetrate thin materials. However, gamma particles have high energy but no mass, and can only be stopped by thick and dense materials such as lead or concrete. Therefore, the correct answer is (d) gamma particles only, as they will not be stopped by the aluminum foil.