Given: Sound Intensity ( I ) = 
We know, the approximate threshold of human hearing is at 1kHz. In watts/m^2 it's value is 
⁻¹² W/m².
So, we can say, Reference sound intensity
= 10⁻¹² W/m².
We have formula for "sound intensity level LI in dB" when entering sound intensity.
LI = 10×log (I / Io) in dB
Plugging values of I and Io in formula.
LI = 10 × log (
)
LI = 10 × log (99000000)
= 10 × 7.99564
LI = 79.96 dB.
Therefore, 79.96 dB is the sound level for a noise that has an intensity of 9.9 × 10-5 watts/m2.
Answer:
2.22m/s
Step-by-step explanation:
Distance = Velocity/Time
533.33m = V/4minutes
V = 533.33/240 seconds
V = 2.22m/s
Answer:
Answer is the third one/ or c
Step-by-step explanation:
<h2>Answer:</h2>
11 and 15
<h2>Explanations:</h2>
Given the arithmetic sequence -1, 3, 7 __, __, you are to find the next two terms of the sequence.
The nth term of an arithmetic sequence is given as;
where:
• a is the ,first term
,
• n is the ,number of terms
,
• d is the ,common difference
From the given sequence;
a = -1
d = 3 - (-1) = 7 - 3 = 4
For the fourth term, n = 4;
For the fifth term, n = 5;
Therefore the next two terms of the arithmetic sequence are 11 and 15.
