In: Physics
Select all true statements.
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 The threshold of human hearing is defined as having an intensity of exactly one W/m2.  | 
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 Sound is a longitudinal wave in air.  | 
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 Sound waves travel faster through gases than through solids.  | 
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 The sound of a horn approaching a stationary observer will have higher frequency than the frequency of the horn at rest.  | 
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 All other variables being equal, the speed of sound in air decreases as the air temperature becomes colder.  |