A sound measures 42 dB. The intensity of a second sound is four times as great. What is the decibel level of this

second sound?

Answers

Answer 1

Answer:

The decibel level of this second sound is 48.021 decibels.

Step-by-step explanation:

The acoustic intensity ([tex]B_{dB}[/tex]), measured in decibels, is defined by the following formula:

[tex]B_{dB} = 10\cdot \log_{10}\left(\frac{I}{I_{o}} \right)[/tex] (1)

Where:

[tex]I_{o}[/tex] - Reference sound intensity, measured in watts per square meter.

[tex]I[/tex] - Real sound intensity, measured in watts per square meter.

If we know that [tex]B_{dB} = 42\,dB[/tex] and [tex]I_{o} = 10^{-12}\,\frac{W}{m^{2}}[/tex], then the real sound intensity of the first sound is:

[tex]\frac{B_{dB}}{10} = \log_{10}\left(\frac{I}{I_{o}} \right)[/tex]

[tex]\frac{I}{I_{o}} = 10^{\frac{B_{dB}}{10} }[/tex]

[tex]I = I_{o}\cdot 10^{\frac{B_{dB}}{10} }[/tex]

[tex]I = \left(10^{-12}\,\frac{W}{m^{2}} \right)\cdot 10^{\frac{42\,dB}{10} }[/tex]

[tex]I = 1.585\times 10^{-8}\,\frac{W}{m^{2}}[/tex]

The real sound intensity of the second sound is four times greater, that is:

[tex]I' = 6.340\times 10^{-8}\,\frac{W}{m^{2}}[/tex]

If we know that [tex]I_{o} = 10^{-12}\,\frac{W}{m^{2}}[/tex] and [tex]I' = 6.340\times 10^{-8}\,\frac{W}{m^{2}}[/tex], then the acoustic intensity of the second sound is:

[tex]B_{dB} = 10\cdot \log_{10}\left(\frac{I'}{I_{o}} \right)[/tex]

[tex]B_{dB} = 10\cdot \log_{10}\left(\frac{6.340\times 10^{-8}\,\frac{W}{m^{2}} }{10^{-12}\,\frac{W}{m^{2}} } \right)[/tex]

[tex]B_{dB} = 48.021\,dB[/tex]

The decibel level of this second sound is 48.021 decibels.


Related Questions

Determine whether or not the following graph represents two quantities that are proportional to each other. Explain your reasoning.

Answers

Answer:

The quantities are not proportional.

Step-by-step explanation:

The values, x and y, do not begin or pass through the origin, (0,0). This means they are not proportional.

The graph represents two quantities are not proportional to each other.

What is Proportional?

A relationship is proportional if each pair of data values are related in the same way, by multiplying by a factor. You can recognize a proportional relationship by looking at data, an equation, or a graph.

Given:

As, A relationship is proportionate if its graph is a line or ray that passes through the origin.

and, It is not proportionate if the line or ray does not go through the origin. Additionally, if anything is not linear, it is not proportional.

Here the graph also does not pass through the origin.

Hence, the graph is not proportional.

Learn more about Proportional here:

https://brainly.com/question/7096655

#SPJ2

a street sign is 104 inches tall. How tall is it in feet and inches.

Answers

Answer:

8 ft 8 in

Step-by-step explanation:

104/12 = 8.666...

This shows that there are 8 total feet because there are 12 inches in a foot

Then, multiply 8*12 to get 96 in order to get the remainder of the inches left that do not make up one whole foot.

Then subtract 96 from 104 (104-96) to get the remainder which is 8 inches.

The polygons are similar. Solve for x.

scale factor from A to B = 3:5

Answers

Answer:

9

Step-by-step explanation:

if scale factor is 3/5, then

(x+12):35=3:5, ⇒

[tex]\frac{x+12}{35} =\frac{3}{5}; x=21-12; x=9[/tex]

Find the value of each expression
-22-(-5)

Answers

Answer:

-17

Step-by-step explanation:

-22-(-5) = -22+5 = -17

Answer:

the answer is -17

Step-by-step explanation:

-22-(5)-22+5=-17

Danny purchases a shirt for $30. The store charges him 8% sales tax on the purchase. How much sales tax will the store charge on the purchase?

Answers

Answer:

tax = $30.00 * 8% tax = $30.00 * 0.08 tax = $2.40

Step-by-step explanation:

luke bought 6 pretzels for himself and friends he spent a total of $13.50 let p represent the price of one pretzel​

Answers

Answer:

6p=$13.50

Step-by-step explanation:

Calculate the quotient. Use paper to show all calculations. Enter your answer in the box below.
6/7 divided by 7 1/2

Answers

Answer:

4/35

Step-by-step explanation:

1. Find 7 1/2

15/2

2. Flip 15/2

2/15

3. Multiply

12/105

4. Simplify

4/35

A triangle has a base of 16" in height of 1/8 inch what is the area?

Answers

Answer:

Area of triangle is 1 inches²

Step-by-step explanation:

We are given:

Base of triangle = 16 inches

Height of triangle = [tex]\frac{1}{8} \:[/tex] inches

We need to find:

Area of triangle

The formula used to find Area of triangle is:

[tex]Area \:of\: triangle=\frac{1}{2}\times b \times h[/tex]

where b is base and h is height.

Putting values and finding area:

[tex]Area \:of\: triangle=\frac{1}{2}\times 16 \times \frac{1}{8}\\ Area \:of\: triangle=\frac{16}{16}\\ Area \:of\: triangle=1\:inches^2[/tex]

So,  Area of triangle is 1 inches²

solve the question below

Answers

Answer:

The answer is below

Step-by-step explanation:

1) A triangle is a polygon with three sides and three angles. There are different types of triangles such as obtuse, scalene, right angle, equilateral and isosceles triangle.

Given that triangle ABC is right angled and AC = 25 cm = hypotenuse and BC = 15 cm. Using Pythagoras:

AC² = BC² + AB²

25² = AB² + 15²

AB² = 25² - 15²

AB² = 400

AB = √400

AB = 20 cm

Using sine rule:

[tex]\frac{sin(B)}{AC}=\frac{sin(A)}{BC}=\frac{sin(C)}{AB}\\\\But\ \angle B= 90^o(right\ angle)\ hence:\\\\ \frac{sin(B)}{AC}=\frac{sin(A)}{BC}\\\\\frac{sin(90)}{25}=\frac{sin(A)}{15}\\\\sin(A)=\frac{sin(90)}{25}*15\\\\sin(A)=0.6\\\\A=sin^{-1}(0.6)\\\\A=36.87^o[/tex]

2)

Using Pythagoras:

hypotenuse² = 8² + 6²

hypotenuse² = 100

hypotenuse = √100

hypotenuse = 10

Using sine rule:

[tex]\frac{sin(x)}{8}=\frac{sin(90)}{10}\\\\sin(x)=\frac{sin(90)}{10}*8\\\\sin(x)=0.8\\\\x=sin^{-1}(0.8)\\\\x=53.13 ^o[/tex]

Factor the polynomial:
462 + 15b - 4

Answers

Answer:

15([tex]\frac{458}{15}[/tex]+b) or

15(b+[tex]\frac{458}{15}[/tex])

Step-by-step explanation:

First we can subtract the 4.

458 + 15b

Now we need to find the GCF, but they do not share any kinds of factors together. This might look ugly, but it is what it is. We factor out 15 to get b by itself.

15([tex]\frac{458}{15}[/tex]+b) or

15(b+[tex]\frac{458}{15}[/tex])

PLEASE SOMEONE HELP ME WITH MY HOMEWORK ILL GIVE BRAINLIST TO WHOEVER GETS THIS RIGHT

Answers

Answer:

First one is sin 27 and cos 63

second one is sin 60

Step-by-step explanation:

This is marked as wrong? Can anyone please correct my mistake?

Answers

Answer:

y - 0 = -⅔(x - 3)

Step-by-step explanation:

Given a point, (a, b) and slope, m, equation of the line in point-slope form can be written.

Thus:

Substitute (a b) = (3, 0), and m = -⅔ into y - b = m(x - a).

y - 0 = -⅔(x - 3) (the equation in point-slope form)

why do planets orbit

Answers

Answer:

Newton realized that the reason the planets orbit the Sun is related to why objects fall to Earth when we drop them. The Sun's gravity pulls on the planets, just as Earth's gravity pulls down anything that is not held up by some other force and keeps you and me on the ground.

Step-by-step explanation:

The suns gravity pulls on the planets, just like how Earths gravity pulls on objects when we drop them.

0.62 devided by 3 please

Answers

Answer:

0.206 and then it repeats 6 over and over again

Step-by-step explanation:

hope it helped :)

Answer:

hey there!

Step-by-step explanation:

the answer is:

0.20666666666

hope it helped and have a nice day!

What three pairs of numbers have 5 as there greatest common factor?

Answers

Answer:

10 and 15, 20 and 25, and 35 and 45.

Step-by-step explanation:

2 divided by 9/10 (in fraction or mixed number form)

Answers

Answer:

decimal: 2.22 mixed number: 2 2/9

estimate 7/8 of 4/5. I will give brainiest

Answers

0.7 I think is the answer. I just looked it up

Answer:

0.7

Step-by-step explanation: I used a calculator.

A speed skater skates 1.5 km in 78 s. What is her speed in km/h? Round to the nearest

Answers

Answer:

Step-by-step explanation:

Speed=Distance/Time

1.5/78=0.01923076923

Answer rounded=0.02/0.019

1) The perimeter of a square is 16 inches. What is the length of each side?
4 inches
8 inches
64 inches
32 inches
Done >

Answers

4 inches because a square has 4 sides 16 divided by 4 is 4
4

16 divided by 4 = 4

Apply the Distributive Property and simplify.
- 8(x + 3) = 24
- 8x +
= 24

Answers

Answer:

x=-6

Step-by-step explanation:

-8(x+3)=24 first, divide both sides to get x+3=-3

then move the constant to the right and change its sign to get x=-3-3 and calculate to get your answer.

hope this helps!

Point A is located at (8, 7) and Point B is located at (0, 5) find the midpoint of line segment overline AB .

Answers

Answer:

The midpoint of the line segment   D = ( 4, 6)  

Step-by-step explanation:

Explanation:-

Given points are A(8,7) and B(0,5)

The midpoint of line segment overline AB

Let 'D' be the midpoint of AB

[tex]D= (\frac{x_{1} + x_{2} }{2} , \frac{y_{1} +y_{2} }{2} )[/tex]

[tex]D = (\frac{8+0}{2} , \frac{7+5}{2} )[/tex]

[tex]D = (\frac{8}{2} , \frac{12}{2} )[/tex]

The midpoint of the line segment

 D = ( 4, 6)  

Simplify 32 ⋅ 35. (4 points)

Question 3 options:

1)

37

2)

310

3)

97

4)

910

Answers

Answer:

Jul 25, 2019 — Click here to get an answer to your question ✍️ 3. Simplify 32 • 35 ... 3. Simplify 32 • 35. (4 points) 37 310 97 910. 2. See answers. Log in to ...

2 answers

Step-by-step explanation:

can you help me i have only one day

Answers

Answer:

n = -1.825

Step-by-step explanation:

8n + 16.2 = 1.6 (Given)

8n = -14.6 (Subtract 16.2 on both sides)

n = -1.825 (Divide 8 on both sides)

Step-by-step explanation:

Move all terms not containing  

n

to the right side of the equation.

Tap for fewer steps...

Subtract  

16.2

from both sides of the equation.

8

n

=

1.6

16.2

Subtract  

16.2

from  

1.6

.

8

n

=

14.6

Divide each term by  

8

and simplify.

Tap for fewer steps...

Divide each term in  

8

n

=

14.6

by  

8

.

8

n

8

=

14.6

8

Cancel the common factor of  

8

.

Tap for more steps...

n

=

14.6

8

Divide  

14.6

by  

8

.

n

=

1.825

Pls help on #10 will give brainliest

Answers

The answer is A hope this helps

. log 3x4
Expand each expression

Answers

Answer:

12

Step-by-step explanation:

because 3x4 is 12

Please any help with steps

Answers

I think the answer is 1/2. C.

Answer:

C

Step-by-step explanation:

1 inch=400 miles

x =200 miles

200 is half of 400, so the measurement should be halved as well.

Which numerical expression represents, two fifths of the product of five eighths and sixteen? please help

Answers

9514 1404 393

Answer:

  [tex]\dfrac{2}{5}\times\left(\dfrac{5}{8}\times 16\right)[/tex]

Step-by-step explanation:

In this context, "of" means "times". A product of two numbers is computed by taking one "times" the other. In short, the operations being described by the words are two uses of "times". That shows up in only one answer choice.

12 The sixth grade at Johnson Middle School set a goal to raise $8,000 for their end-of -the-year field trip to Washington DC. September December March $10,000 $10,000 $9,000 $9,000 $8,000 Goal $7,000 $10,000 $9,000 $8,000 Goal $8,000 Goal $7,000 $7,000 $6,000 $5,000 $6,000 $5,000 $4,000 $3,000 $2,000 $1,000 $6,000 $5,000 $4,000 $4,000 $3,000 $3,000 $2,000 $1,000 $2,000 $1,000 60 Grade Grade 6 Grade (a) On the first day of school, Bethany's family donated $60 to the field trip fundraiser. What percent of their total goal did Bethany's family donate? F 0.75% G 75% H 2.5% J 0.25%​

Answers

Answer:

0.75%

Step-by-step explanation:

Total amount to generate at fundraiser = $8000

Amount donated by Bethany family = $60

The percentage of Bethany's donation towards the fundraiser is :

Let percentage = x

x% of 8000 = 60

x/100 * 8000 = 60

0.01x * 8000 = 60

80x = 60

Divide both sides by des by 80

80x / 80 = 60 / 80

x = 0.75

The student council needs posters for the Winter Carnival. The print shop charges $15 for each print job. Each poster will cost an additional
$1.35.
Which equation shows the relationship between the number of posters, n, and the total cost, c, in dollars?

O A. c = 1.35n + 15
O B. n = 1.35n + 15
O C. c = 16.35n
O D. n = 16.35c

Answers

Answer: A. c = 1.35n + 15

Step-by-step explanation:

Given: Charge for each job = $15

Additional cost per poster = $ 1.35

Total cost = Charge for each job + (Additional cost per poster) (Number of posters)     ...(i)

Varaibles:

c= Tota; cost for n posters.

Substitute all values in (i), we get

[tex]c=15+1.35n[/tex]

Hence, the required equation : c = 1.35n + 15

Hence, the correct option is A. c = 1.35n + 15.

What is M - 3 > -2???

Answers

Answer:

m>1

Step-by-step explanation:

inverse operations... add 3 to both sides so you get -2+3=1!!

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