A Radioactive Source Has a Half-Life of 2 Min $\times$ 10⁶
B)1

question 87

Multiple Choice

A radioactive source has a half-life of 2 min.At time t = 0 it is placed near a detector and the counting rate is observed to be 3000 counts/s.If the detection efficiency is 25%,how many radioactive nuclei are there at time t = 0?

• A)1.04 \(\times\) 10⁶
• B)1.67 \(\times\) 10⁶
• C)2.08 \(\times\) 10⁶
• D)3.41 \(\times\) 10⁶
• E)3.79 \(\times\) 10⁶

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Definitions:

Lateral Transport

The movement of substances parallel to the surface of a cell membrane, often involved in various cellular processes.

Lenticels

Porous swellings of cork cells in the stems of woody plants; facilitate the exchange of gases.

Pith Rays

Tissue in plants that extends radially across the stem or trunk, involved in the storage and transport of nutrients horizontally within the structure.

Heartwood

The dense, inner part of a tree trunk, yielding the hardest wood.