Iridium-192 Has a Half-Life of 74 Days

question 47

Multiple Choice

Iridium-192 has a half-life of 74 days. How long will it take for 75% of the isotope to decay?

• A)74 days
• B)111 days
• C)37 days
• D)185 days
• E)148 days

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Definitions:

Reptiles

Cold-blooded vertebrates that breathe air, usually lay eggs, and have scales covering their bodies, including snakes, lizards, crocodiles, and turtles.

Chordates

Deuterostome animals that, at some time in their lives, have a cartilaginous, dorsal skeletal structure called a notochord; a dorsal, tubular nerve cord; pharyngeal slits; a postanal tail; and an endostyle (or its derivative, a thyroid gland).

Cyanobacteria

Photosynthetic microorganisms, formerly known as blue-green algae, that are important in oxygen production and nitrogen fixation.

Marine Invertebrates

Animals without a backbone that live in marine environments, including species like jellyfish, sea stars, and corals.