How Many Half-Lives Are Needed for a 400

question 60

Multiple Choice

How many half-lives are needed for a 400.0 ng sample of a radioactive isotope to decay to 12.5 ng?

• A)4
• B)5
• C)10
• D)16
• E)32

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Definitions:

Compounded Annually

Interest on an investment or loan that is calculated once a year and added to the principal amount, allowing the investment to grow at an increasing rate.

Discounting

The process of determining the present value of a payment or a stream of payments to be received in the future, by applying a discount rate.

Compound Annual

An interest rate calculation method that accounts for the effect of compounding over a one-year period.

Salary Growth

The increase in wages or salary over time, often due to inflation, promotion, or successful performance.