Strontium 90, a Radioactive Isotope of Strontium, Is Present in the Fallout

question 72

Multiple Choice

Strontium 90, a radioactive isotope of strontium, is present in the fallout resulting from nuclear explosions. It is especially hazardous to animal life, including humans, because, upon ingestion of contaminated food, it is absorbed into the bone structure. Its half-life is 27 years. If the amount of strontium 90 in a certain area is found to be four times the "safe" level, find how much time must elapse before an "acceptable level" is reached.

• A) 30.3 year(s) must elapse before an "acceptable level" is reached.
• B) 54 year(s) must elapse before an "acceptable level" is reached.
• C) 57 year(s) must elapse before an "acceptable level" is reached.
• D) 39 year(s) must elapse before an "acceptable level" is reached.

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Definitions:

Retained Earnings

The portion of a business's profits not distributed to shareholders but reinvested in the business or held for future use.

Surplus Cash

Excess funds that a company retains over its necessary working capital and capital expenditure requirements, often available for investment or distribution.

Dividends

A portion of a company's earnings distributed to shareholders, often in the form of cash or additional stock.

Internal Revenue Code

The comprehensive set of tax laws in the United States, governed by the Internal Revenue Service (IRS), that dictates federal tax obligations.