which of the following choices correctly describes the decreasing ability of the radiation to penetrate a sheet of lead that is 3 inches thick?

A. alpha particles > beta particles > gamm rays
B. gamma rays > alpha particles > beta particles
C. alpha particles > gamma rays > beta particles
D. beta particles > alpha particles > gamma rays
E. gamma rays > beta particles > alhpa particles

It is really a bad question. The alpha particles will interact with matter, and have a very short range, and the beta will interact with conductors (metals) and not penetrate them either. So in fact, on lead, both alpha and beta penetration ranges are nil. Of course, Gamma penetrates to a long depth.

In view of this, either answers b or e are correct, technically, for lead. E probably is what your instructor wants as the "correct" answer.

no wonder this question didn't make sense to me.

I understand your confusion with this question, and you are correct in pointing out that it may not be well-designed. The options given do not accurately describe the ability of radiation to penetrate a sheet of lead that is 3 inches thick.

It is true that alpha particles are easily stopped by a sheet of lead, as they have a short range and interact strongly with matter. Beta particles, on the other hand, can be stopped by conductive materials like metals such as lead. So, both alpha and beta particles would have negligible penetration ranges in lead, as you mentioned.

Gamma rays, being a type of electromagnetic radiation, have much higher penetrating power. They can travel through thick materials, including lead, depending on their energy. Therefore, in the context of lead as the material, option E (gamma rays > beta particles > alpha particles) is the most accurate, as it acknowledges that gamma rays can penetrate lead the furthest.

I apologize for the confusion caused by this question. It is important to critically analyze and question the accuracy of the given options when encountering such situations.