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3 years ago

A 90dB sound wave strikes an eardrum whose area is 5.0×10^-5m^2. How much energy is absorbed by the eardrum per second

Physics

1 answer:

MakcuM [25]3 years ago

6 0

-- The reference level for sound wave intensity is the threshold of human hearing, defined as 10⁻¹² W/m² .

-- This question is talking about a 90dB sound. So its intensity is 10⁻³ W/m² .

-- The question tells us the size of the area that this sound is hitting. So the power absorbed by that area is ...

Power = (intensity) x (area)

Power = (10⁻³ W/m²) x (5 x 10⁻⁵ m²)

Power = (10⁻³ x 5 x 10⁻⁵) W

<em>Power = 5 x 10⁻⁸ Watts</em>

(That's 5 x 10⁻⁸ Joules of energy per second.)

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