Why are there so many different ways to measure Radioactivity, and how do those methods relate to each other?

Question

I have always had a hard time grasping this. Radioactivity has many units of measure: Grays, Rads, Rems, Curies, Roentgen, Sieverts, Becquerels.

Why are there so many different unit types, and how do they inter-relate? I have a decent understanding of physics, but not in this specific area. To date I haven’t read or heard an explanation that gives an “ah-ha!” moment or makes me quite understand what all these measures actually mean.

Yes, I have seen the XKCD radioactivity chart.

In: Physics

Answer 1

> Radioactivity has many units of measure: Grays, Rads, Rems, Curies, Roentgen, Sieverts, Becquerels.

You forgot [Banana Equivalent Dose.](https://en.wikipedia.org/wiki/Banana_equivalent_dose)