170 students in a lecture hall can scream at 115 dB.
Thus, we should expect that:
A. an average student can do 0.68 dB by him or herself.
B.340 average students can do 125 dB.
C.340 average students can do 230 dB.
D.1700 average students can do 125 dB.
E.85 average students can do 105 dB.
F.the loudest student in the class can do 115 dB.
an increase of 10db reflects a tenfold increase in sound power.
To determine the answer to this question, we need to use the concept of sound intensity level and consider how it changes with the number of students.
The sound intensity level is measured in decibels (dB), which is a logarithmic scale. The formula for sound intensity level is:
L = 10 log10(I/I0)
Where L is the sound intensity level in dB, I is the sound intensity (in W/m^2), and I0 is the reference sound intensity (usually taken as the threshold of hearing, which is approximately 1e-12 W/m^2).
From the given information, we know that when there are 170 students screaming, the sound intensity level is 115 dB.
Now, we can use this information to find the answer:
A. an average student can do 0.68 dB by him or herself.
To determine if this is correct, we would need to know the sound intensity level produced by a single student. However, this information is not given, so we cannot determine if this statement is true or false.
B. 340 average students can do 125 dB.
To determine if this is correct, we can use the formula mentioned earlier. If we assume that the sound intensity level is directly proportional to the number of students, we can set up a proportion:
115 dB -------- 170 students
125 dB -------- x students
Cross-multiplying, we get:
115x = 170 * 125
x = (170 * 125) / 115
x ≈ 184.78
So, the statement is false. 340 average students would actually produce a higher sound intensity level than 125 dB.
C. 340 average students can do 230 dB.
Similarly, using the same approach, we can see that this statement is also false. 340 average students would not be able to produce a sound intensity level of 230 dB.
D. 1700 average students can do 125 dB.
Using the previously explained method, we can set up the proportion:
115 dB -------- 170 students
125 dB -------- x students
Cross-multiplying, we get:
115x = 170 * 125
x = (170 * 125) / 115
x ≈ 184.78
So, the statement is false. 1700 average students would actually produce a higher sound intensity level than 125 dB.
E. 85 average students can do 105 dB.
We can set up the proportion to test this statement:
115 dB -------- 170 students
105 dB -------- x students
Cross-multiplying, we get:
115x = 170 * 105
x = (170 * 105) / 115
x ≈ 155.22
So, the statement is false. 85 average students would actually produce a lower sound intensity level than 105 dB.
F. the loudest student in the class can do 115 dB.
This statement is correct because it is stated in the question that with 170 students screaming, the sound intensity level is 115 dB. So, the loudest student in the class can indeed produce 115 dB.
Therefore, the correct answer is: F. The loudest student in the class can do 115 dB.