The Isotope Has a Half-Life of 7

question 65

Multiple Choice

The isotope has a half-life of 7.5 seconds. If a sample contains 144 atoms of , approximately how many such atoms were there present 30 seconds earlier?

• A) 576
• B) 1152
• C) 2304
• D) 4320
• E) 4.30 × 10⁸

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Definitions:

Present Value

Today's equivalent value of a forthcoming sum of money or stream of payments, according to a specified interest rate.

Compound Interest

This refers to the method of calculating interest where the amount is based on the initial principal as well as the interest that has accumulated over prior periods for a loan or deposit.

Future Value

The value of an asset or cash at a specific future date, based on its expected growth over time.

Compounded Monthly

Interest calculation method where the accrued interest is added to the principal sum each month, leading to interest on interest.