A Certain Substance Has a Half-Life of 5

question 81

Multiple Choice

A certain substance has a half-life of 5.0 hours. How many nuclei of the substance are required to give an initial activity of 6.0 μCi? 1 Ci = 3.7 × 10¹⁰ Bq.

• A) 5.8 × 10⁹ nuclei
• B) 8.5 × 10⁸ nuclei
• C) 6.3 × 10⁸ nuclei
• D) 3.2 × 10⁹ nuclei
• E) 2.4 × 10⁹ nuclei

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Definitions:

Methane

A potent greenhouse gas with a significant impact on global warming, primarily produced from decomposition of organic matter and the digestive processes of certain animals.

Carbon Dioxide

A gas that has no color or smell, created when carbon and organic compounds burn and during breathing. It exists naturally in the atmosphere and is taken in by plants during the process of photosynthesis.

Ultraviolet Radiation

A form of electromagnetic radiation with wavelengths shorter than visible light but longer than X-rays, capable of causing skin burns and can play a beneficial role in vitamin D production.

Ozone Layer

The ozone layer is a stratospheric layer rich in ozone, which protects life on Earth by absorbing the majority of the sun's harmful ultraviolet radiation.