Half-Life

What is the remaining amount of a substance after 3 half-lives if you start with 80 g?

• 5 g

• 10 g

• 20 g

• 15 g

What is the significance of knowing the half-life of a radioactive isotope?

• It helps in predicting how long it will take for a certain amount of the isotope to decay, which is crucial in fields like medicine, archaeology, and nuclear energy.

• It determines the color of the isotope when it is exposed to light.

• It indicates the temperature at which the isotope becomes stable.

• It provides information about the isotope's atomic number.

If the half-life of an isotope is known, how can you determine the number of half-lives that have passed?

• By measuring the temperature of the isotope

• By comparing the initial amount of the isotope to the remaining amount and using the formula: n = log(final amount/initial amount) / log(1/2)

• By calculating the total time elapsed since the isotope was formed

• By observing the color change of the isotope over time

If a radioactive isotope has a half-life of 10 seconds, how much of a 100 g sample remains after 30 seconds?

• 0 g

• 25 g

• 12.5 g

• 50 g

What happens to the percentage of the parent isotope as more half-lives pass?

• The percentage of the parent isotope remains constant.

• The percentage of the parent isotope decreases linearly.

• The percentage of the parent isotope decreases exponentially.

• The percentage of the parent isotope increases.

How do you calculate the remaining percentage of a parent isotope after a certain number of half-lives?

• Remaining % = (1/2)^n * 100%

• Remaining % = n * 50%

• Remaining % = 100% - (n * 10%)

• Remaining % = (1/2)^(n/2) * 100%

What is the half-life of uranium-232?

• 50 years

• 70 years

• 100 years

• 150 years

What is alpha decay?

• A type of radioactive decay where an atomic nucleus emits an alpha particle (2 protons and 2 neutrons), resulting in a new element.

• A process where an atomic nucleus absorbs a neutron and becomes unstable.

• A form of nuclear fission that splits an atomic nucleus into smaller parts.

• A reaction where an atom gains electrons and becomes negatively charged.

Why is it important to understand radioactive decay in nuclear medicine?

• It helps in determining dosages and treatment plans.

• It is only relevant for research purposes.

• It has no impact on patient safety.

• It is used to calculate the cost of treatments.

What is the relationship between half-life and the stability of an isotope?

• Isotopes with shorter half-lives are more stable than those with longer half-lives.

• There is no relationship between half-life and stability of isotopes.

• Generally, isotopes with longer half-lives are more stable than those with shorter half-lives.

• Isotopes with longer half-lives decay faster than those with shorter half-lives.