The curie measures the activity defined as the disintegration rate of what?

The curie measures the activity defined as the disintegration rate of what?

• A. 1 disintegration per second
• B. 1 disintegration per minute
• C. 3.7 x 10^10 disintegrations per second per gram of radium-226
• D. 1 joule per decay

Answer: (C)

The main idea is that activity is a rate: how many radioactive decays occur each second. The curie is defined as 3.7 × 10^10 disintegrations per second. This value comes from the activity of radium‑226, specifically the activity of 1 gram of radium‑226. So a quantity of material with an activity of 1 curie is decaying at 3.7 × 10^10 times per second per gram of radium‑226. This is a rate, not energy per decay, and not per minute. That’s why the best answer is the one that states 3.7 × 10^10 disintegrations per second per gram of radium‑226.

The main idea is that activity is a rate: how many radioactive decays occur each second. The curie is defined as 3.7 × 10^10 disintegrations per second. This value comes from the activity of radium‑226, specifically the activity of 1 gram of radium‑226. So a quantity of material with an activity of 1 curie is decaying at 3.7 × 10^10 times per second per gram of radium‑226. This is a rate, not energy per decay, and not per minute. That’s why the best answer is the one that states 3.7 × 10^10 disintegrations per second per gram of radium‑226.