Half Life Flashcards
Atomic Structure (16 cards)
What is radioactivity?
Radioactivity is the process by which radioactive substances emit radiation from the nuclei of their atoms, randomly and unpredictably.
How can radiation be measured?
Radiation can be measured using a Geiger-Muller tube and counter, which records the count-rate of radiation counts per second.
What is radioactive decay?
Radioactive decay is a random process, meaning you cannot predict which nucleus will decay next or when it will happen.
What is half-life?
Half-life is the time it takes for the amount of radiation emitted by a source to halve.
What does half-life allow us to do?
Half-life allows predictions about radioactive sources, despite their decays being random.
How is activity measured?
Activity is measured in becquerels (Bq), where 1 Bq is equal to 1 decay per second.
What happens to the activity of a radioactive source over time?
The activity of a radioactive source decreases over time as unstable nuclei decay into stable nuclei.
What is the significance of short half-life isotopes?
Short half-life isotopes decay quickly and emit high amounts of radiation initially, making them dangerous.
What does a long half-life indicate about a radioactive source?
A long half-life means the activity decreases slowly, as most nuclei do not decay for a long time, potentially posing long-term radiation exposure risks.
What is the formula to calculate final activity as a percentage after two half-lives?
Final activity percentage = (Final activity / Initial activity) * 100.
What is the activity after one half-life if the initial activity is 640 Bq?
320 Bq.
What is the activity after two half-lives if the initial activity is 640 Bq?
160 Bq.
How can you visualize half-life using a graph?
By plotting a graph of activity against time, the shape will indicate the half-life based on the time interval corresponding to a halving of activity.
True or False: The activity of a radioactive source can eventually reach zero.
False.
Fill in the blank: A radioactive source with a _______ half-life emits radiation for a long duration.
long
Fill in the blank: The unit of measurement for activity is _______.
becquerels (Bq)
