Radioactivity and Decay

What is the unit of measurement for the activity of a radioactive source?

• Seconds

• Becquerels

• Meters

• Joules

The decay constant is defined as the probability of decay of a single nucleus per what unit of time?

• Day

• Second

• Hour

• Minute

In the formula A = λN, what does 'N' represent?

• Number of decayed particles

• Number of particles per second

• Number of particles at a given time

• Number of initial particles

If the initial activity of a source is 3.5 x 10^10 Bq and the decay constant is 0.15 s^-1, what is the initial number of particles?

• 3.5 x 10^10

• 1.5 x 10^10

• 2.33 x 10^11

• 0.15 x 10^11

How do the activity and number of particles change over time?

• Linearly increase

• Linearly decrease

• Exponentially decrease

• Exponentially increase

The mathematical relationship of exponential decay in radioactivity is similar to which other physical concept?

• Electromagnetism

• Capacitors

• Thermodynamics

• Optics

What is the first step in rearranging the decay equation to solve for time?

• Multiply both sides by the decay constant

• Add the decay constant to both sides

• Take the natural logarithm of both sides

• Divide both sides by the initial number of particles

What property of logarithms is used to simplify the equation when solving for time?

• Logarithm of a product

• Logarithm of a quotient

• Logarithm of a power

• Logarithm of a sum

In the context of the decay equation, what do the natural log and 'e' functions do to each other?

• They divide each other

• They cancel each other out

• They add to each other

• They multiply each other

What is the final expression for time when rearranging the decay equation?

• N0 * λ / N

• N / (N0 * λ)

• ln(N/N0) * λ

• ln(N0/N) / λ