An electronic point source emits sound isotropically at a frequency of 3000 Hz and a power of 34 watts. A small microphone has an area of 0.75 cm2 and is located 158 meters from the point source. a) What is the sound intensity at the microphone ?
To find intensity i tried I=Power/Area which is 34/.0075m but its saying my answer is wrong help??
and i don't know how to get others
I = ? W/m2
b) What is the power intercepted by the microphone?
Pin = ? W
c) How many minutes will it take for the microphone to receive 0.3 Joules from this sound?
ΔT = ? min
d) What is the sound intensity level at the microphone from this point source?
Β = ? dB
e) What would be the sound intensity level at the microphone if the point source doubled its power output?
Β = ? dB
ok figured out intensity need help with other 4
It emits a sound, so the equation is Intensity = Power / 4(pi)r^2
r being the distance, 158 meters.
a) The sound intensity at the microphone can be calculated using the formula:
Intensity = Power / Area
Given:
Power = 34 watts
Area = 0.0075 m^2
Substituting the given values into the formula:
Intensity = 34 watts / 0.0075 m^2
Calculating the value of intensity, we get:
Intensity = 4533.33 W/m^2
So the sound intensity at the microphone is approximately 4533.33 W/m^2.
b) The power intercepted by the microphone can be calculated using the formula:
Power = Intensity * Area
Given:
Intensity = 4533.33 W/m^2
Area = 0.0075 m^2
Substituting the given values into the formula:
Power = 4533.33 W/m^2 * 0.0075 m^2
Calculating the value of power, we get:
Power = 34 watts
So the power intercepted by the microphone is 34 watts.
c) To find the time taken to receive 0.3 Joules from the sound, we can use the formula:
Energy = Power * Time
Given:
Energy = 0.3 Joules
Power = 34 watts
Rearranging the formula to solve for time:
Time = Energy / Power
Substituting the given values into the formula:
Time = 0.3 Joules / 34 watts
Calculating the value of time, we get:
Time = 0.0088235 seconds
To convert the time into minutes, we divide by 60:
Time = 0.0088235 seconds / 60
Calculating the value of time in minutes, we get:
Time = 0.00014705 minutes
So it will take approximately 0.00014705 minutes, or about 0.0088 seconds, for the microphone to receive 0.3 Joules from the sound.
d) The sound intensity level at the microphone can be calculated using the formula:
Intensity Level = 10 * log10(Intensity / (10^-12))
Given:
Intensity = 4533.33 W/m^2
Substituting the given value into the formula:
Intensity Level = 10 * log10(4533.33 / (10^-12))
Calculating the value using logarithmic properties, we get:
Intensity Level = 94.78 dB
So the sound intensity level at the microphone from this point source is approximately 94.78 dB.
e) To calculate the sound intensity level at the microphone if the point source doubles its power output, we need to find the new intensity level.
Given:
Original Power = 34 watts
New Power = 2 * Original Power = 2 * 34 watts
Using the previous formula for sound intensity level:
New Intensity Level = 10 * log10((2 * 34) / (10^-12))
Calculating the value using logarithmic properties, we get:
New Intensity Level = 95.28 dB
So the sound intensity level at the microphone would be approximately 95.28 dB if the point source doubled its power output.