Strontium-90 Is a Byproduct in Nuclear Reactors Fueled by the Radioisotope

question 156

Multiple Choice

Strontium-90 is a byproduct in nuclear reactors fueled by the radioisotope uranium-235. The half-life of strontium-90 is 28.8 yr. What percentage of a strontium-90 sample remains after 75.0 yr?

• A)68.1
• B)16.5
• C)7.40
• D)38.4
• E)2.60

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Definitions:

Projection

A defense mechanism where individuals attribute their own unwanted feelings, motives, or thoughts to another person.

Threatening Impulses

Internal desires or drives that are perceived as dangerous or unacceptable, leading to anxiety or psychological discomfort.

Defense Mechanism

Psychological strategies used unconsciously by individuals to protect themselves from anxiety and cope with reality or maintain self-image.

Fixation

An obsessive interest or feeling towards a particular object or idea that can result from unresolved conflicts, particularly those stemming from early childhood.