Understanding Radioactivity and Half-Life

What is the first step when dealing with a graph of the natural log of activity against time?

• Manipulate the expression to match the y-axis

• Determine the initial activity

• Calculate the half-life directly

• Find the decay constant

Which mathematical operation is used to simplify the equation involving the exponential function?

• Dividing by the initial activity

• Taking the square root

• Multiplying by time

• Taking the natural log

What is the relationship between the gradient of the graph and the decay constant?

• The gradient is equal to the decay constant

• The gradient is unrelated to the decay constant

• The gradient is the inverse of the decay constant

• The gradient is the negative of the decay constant

How is the half-life calculated once the decay constant is known?

• By dividing ln(2) by the decay constant

• By multiplying the decay constant by ln(2)

• By adding the decay constant to ln(2)

• By subtracting the decay constant from ln(2)

What approximate value is obtained for the half-life in the example calculation?

• 40 seconds

• 35 seconds

• 30 seconds

• 25 seconds