Radioactive Decay Law Quiz

What does the radioactive decay law primarily describe?

• The exponential decrease of parent nuclei over time

• The constant number of parent nuclei over time

• The linear decrease of parent nuclei over time

• The increase of parent nuclei over time

In the radioactive decay equation, what does N0 represent?

• The number of nuclei at time T

• The decay constant

• The initial number of radioactive nuclei

• The time elapsed

What is the decay constant (lambda) used for in the decay equation?

• To determine the initial number of nuclei

• To calculate the time elapsed

• To describe the rate of decay

• To find the final number of nuclei

How is the activity of a radioactive sample related to the number of radioactive nuclei?

• Activity is inversely proportional to the number of nuclei

• Activity is directly proportional to the number of nuclei

• Activity is unrelated to the number of nuclei

• Activity is the square of the number of nuclei

Which of the following is true about the decay curves for number, activity, and mass?

• They have the same shape

• They have different shapes

• They are unrelated

• They are inversely related

What is the half-life of iodine-131 as mentioned in the video?

• 12.3 days

• 5.5 days

• 8.02 days

• 10.5 days

How many atoms of iodine-131 are initially present in one milligram according to the example?

• 2.60 x 10^21 atoms

• 5.60 x 10^21 atoms

• 3.50 x 10^21 atoms

• 4.60 x 10^21 atoms

After 50 days, how many atoms of iodine-131 remain from the initial one milligram sample?

• 4.12 x 10^-19 atoms

• 7.12 x 10^-19 atoms

• 5.12 x 10^-19 atoms

• 6.12 x 10^-19 atoms

What is the purpose of converting the decay constant into different units like seconds?

• To make calculations easier

• To alter the initial number of nuclei

• To change the half-life

• To express activity in decays per second

Why is it important to use the same unit of time when applying the decay equation?

• To decrease the decay rate

• To increase the decay rate

• To simplify the equation

• To ensure the units cancel out correctly