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aalyn [17]
3 years ago
12

A student is standing 8 m from a roaring truck engine that is measured at 20 db. The student moves 4 m closer to the engine. Wha

t is the measured sound intensity at the new distance?
Biology
2 answers:
tatyana61 [14]3 years ago
7 0

Answer:

The answer to the question above is explained below

Explanation:

The loudness or sound intensity of the roaring truck engine is inversely proportional to the square of the distance.

r1^2 / r2^2 = L2/L1

Where, r1 and r2 = old distance and new distance respectively,

L1 and L2 = old sound intensity and new sound intensity respectively.

From the parameters given above,

r1=8m

r2=4m

L2=?

L1= 20dB

8^2 / 4^2 = L2 / 20 dB

L2 =  80 dB

The answer  is 80 dB. Increased from 20 dB.

Decibel (dB),  is a relative unit of measurement used for expressing the ratio between two physical quantities, usually electric power, or for measuring Sound intensity. Decibels measure the ratio of a given intensity to the threshold of hearing intensity.

Sound intensity, also known as acoustic intensity, is a vector describing the intensity of a sound is proportional to its amplitude squared.

icang [17]3 years ago
3 0

Answer:

80 dB

Explanation:

Sound intensity is inversely proportional to the square of the distance traveled by the sound.

Thus;

r1^2 divide by r2^2 = L2divideL1

where r= distance (m)

L= sound intensity (decibal dB)

8squared divide by 4 squared = L2 divide 20 dB

L2 = 4 × 20

L2= 80 dB

This means that the sound is increased from 20 dB to 80 dB.

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GenAlex Medical, a leading manufacturer of medical laboratory equipment, is designing a new automated system that can detect bor
SashulF [63]

Answer:

The minimum mass of dissolved cholesterol that the new system must be able to detect is 0.43 milligrams.

Note: The question is incomplete. The complete question is:

<em>GenAlex Medical, a leading manufacturer of medical laboratory equipment, is designing a new automated system that can detect borderline high levels of dissolved cholesterol (170, to 200. mg/dL), using a blood sample that is as small as 250 μL Calculate the minimum mass in milligrams of cholesterol that the new system must be able to detect Be sure your answer has the correct number of significant digits.</em>

Explanation:

Range of the equipment to detect cholesterol in blood = 170.0  to 200.0 mg/dL

Minimum amount of cholesterol that can be detected by instrument = 170 mg/dL

Volume of blood sample = 250 <em>μ</em>L= 0.0025 dL (1 dL = 100000 <em>μL)</em>

Amount of dissolved cholesterol in 250 <em>μL</em> sample of blood =

170 mg/dL * 0.0025 dL =  0.425 mg

The minimum mass of cholesterol that the new system must be able to detect is 0.43 milligrams.

7 0
3 years ago
An 8-year-old child undergoes tonsillectomy. what is the priority action in the immediate postoperative period?
lyudmila [28]

Positioning the child on the side (side-lying position) is the priority action after tonsiloectomy. It will permit the flow of secretions (like blood) from the mouth that could block the child's airway (airway patency is the priority). So, the most important thing is to maintain an open airway. Excessive coughing could actually trigger bleeding. The child will be on nothing-by-mouth status during the immediate postoperative period.

4 0
3 years ago
Agrobacterium infects plants and causes them to form tumors. You determine that tumor formation requires a large amount of the p
lianna [129]

Answer:

<em>Agrobacterium</em> <em>tumefaciens</em> is a gram negative bacteria that is responsible for tumor formation in the different parts of plant body.

Explanation:

It causes crown-gall disease in plant body by transferring it's DNA into the plant body which include Ti plasmid.

There are 3 types of bacteria that form tumor in different plant ares.

<em>Agrobacterium rhizogenes</em>,<em> Agrobacterium tumefaciens</em> strains contain either Ti or Ri plasmid but <em>Agrobacterium vitis</em> contain only Ti plasmid   which are virulent.

The transfer of T-DNA takes place into the body of host cells and then the DNA is expressed into the body of the host and thus forming gall or tumor.

8 0
3 years ago
What is one half of a duplicated chromosome called ?
Zina [86]
One half of a duplicated chromosome is called a sister chromatid
7 0
3 years ago
Why is the position of the eyes of a macaw makes it difficult to judge distance
OLEGan [10]
The position of the eyes of a Macaw are as follows. Each eye is located on either side of the birds head. This is called Monocular vision, opposed to our eyes which are located in front of our head, adjacent to each other. Mono comes from the Greek root word meaning 'alone'. Making it understandable that, that type of vision is more limited.  The operation of their eyes, view things differently in comparison to that of binocular vision (what we humans have). They have a more broad view but cannot judge distance or depth very well.
Hope this helps! If you have any other questions or would like further explanation just let me know! :)

7 0
3 years ago
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