Understanding Radioactive Half-Life

What characteristic of nuclear radiation makes it unpredictable?

• It is visible to the naked eye.

• It is random and spontaneous.

• It is affected by temperature.

• It is always decaying.

According to the law of large numbers, what happens when you flip a coin a large number of times?

• The coin will land on its edge.

• The fraction of heads and tails will be close to 50%.

• The results will be unpredictable.

• The coin will always land on heads.

What does the half-life of a radioactive substance represent?

• The time it takes for all atoms to decay.

• The time it takes for half of the sample to decay.

• The time it takes for the substance to become non-radioactive.

• The time it takes for the substance to double in mass.

If a sample has a half-life of 10 minutes, how much of the original sample remains after 20 minutes?

• Half of the original sample remains.

• One-fourth of the original sample remains.

• None of the original sample remains.

• All of the original sample remains.

What is a common misconception about half-life?

• Half-life is the time for the entire sample to decay.

• Half-life is the time for the sample to double in mass.

• Half-life is the time for the sample to become non-radioactive.

• Half-life is the time for half of the remaining sample to decay.

What is the unit of radioactivity?

• Becquerel

• Joule

• Newton

• Watt

How does the mass-time graph of a radioactive isotope typically appear?

• A zigzag pattern

• A parabolic curve

• An exponential decay curve

• A straight line

What happens to the mass of the daughter isotope as the original isotope decays?

• It increases.

• It remains constant.

• It fluctuates randomly.

• It decreases.

In a mass-time graph, what does the x-axis typically represent?

• Mass

• Time

• Temperature

• Radioactivity

If a radioisotope has an activity of 400 Bq and a half-life of 8 days, what is its activity after 32 days?

• 400 Bq

• 50 Bq

• 25 Bq

• 200 Bq