Two Boys Are Whispering in the Library

question 50

Multiple Choice

Two boys are whispering in the library. The radiated sound power from one boy's mouth is 1.2 × 10^-9 W; and it spreads out uniformly in all directions. What is the minimum distance the boys must be away from the librarian so that she will not be able to hear them? The threshold of hearing for the librarian is 1.00 × 10^-12 W/m².

• A)100 m
• B)35 m
• C)23 m
• D)16 m
• E)9.8 m

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Definitions:

Object Permanence

The understanding that objects continue to exist even when they cannot be observed.

Direct Perception

The theory that the environment provides all necessary cues for perception, which can be directly grasped without additional cognitive processes.

Cognitive Psychologist

A professional who studies mental processes such as perception, thought, memory, and reasoning.

Nationality

Refers to the belonging or affiliation of an individual to a specific nation either by birth or naturalization.