Question

a small amount of americium-241 is used in smoke detectors. a stream of radiation flows between two electrodes. if smoke interrupts the stream, the alarm goes off. what feature of the radioisotope americium-241 would be most helpful for the smoke detector to work?
long half-life
short half-life
over-sensitive detection
less sensitive detection

Explanation:

Smoke detectors need a radioisotope that emits radiation steadily over a long period. A long half - life means the americium - 241 will emit radiation consistently for a long time, so the detector can work reliably without the radioisotope decaying too quickly. A short half - life would mean the isotope decays fast and the detector would stop working properly. Over - sensitive or less sensitive detection are not related to the radioisotope's inherent property for the detector's long - term functionality, but rather to the detector's design. So the long half - life of americium - 241 is most helpful.

Answer:

A. long half - life