what is the variation of pressure in the sound wave if the sound intensity is 3.85x10^-8 W/m^2, the speed of sound is 343 m/s and the density of air is 1.2 kg/m3?
To find the variation of pressure in a sound wave, you can use the formula:
ΔP = √(2 * ρ * c * I)
Where:
ΔP is the variation of pressure
ρ is the density of air
c is the speed of sound
I is the intensity of the sound wave
Given:
ρ = 1.2 kg/m^3
c = 343 m/s
I = 3.85 x 10^-8 W/m^2
Now, we can substitute these values into the formula and calculate the variation of pressure:
ΔP = √(2 * 1.2 kg/m^3 * 343 m/s * 3.85 x 10^-8 W/m^2)
First, let's simplify the inside of the square root:
2 * 1.2 kg/m^3 * 343 m/s * 3.85 x 10^-8 W/m^2 = 2.9688 x 10^-6
Now, let's substitute this value back into the formula:
ΔP = √(2.9688 x 10^-6)
Finally, calculate the square root:
ΔP ≈ 0.0017 Pa (rounding to 3 decimal places)
Therefore, the variation of pressure in the sound wave is approximately 0.0017 Pascal (Pa).