In the absence of the teacher, the noise level in a classroom containing 50 students is 50 dB . Assuming that each student, on average, emits the same sound energy per second, determine the noise level if the number of students increases to

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In the absence of the teacher, the noise level in a classroom containing 50 students is 50 dB . Assuming that each student, on average, emits the same sound energy per second, determine the noise level if the number of students increases to 100 .

Quantrex Academy · Accepted Answer

Correct answer: B. 53 dB

Let the sound intensity produced by one student be I_ s and the reference intensity be I₀ . The total intensity produced by 50 students is I₁ = 50I_ s . The noise level is given by L₁ = 10 ₁₀ ( I₁ I₀ ) = 50 dB . When the number of students increases to 100 , the new intensity is I₂ = 100I_ s . The new noise level is L₂ = 10 ₁₀ ( I₂ I₀ ) . The difference in noise levels is L₂ - L₁ = 10 ₁₀ ( I₂ I₁ ) . Substituting the values, L₂ - 50 = 10 ₁₀ ( 100I_ s 50I_ s ) = 10 ₁₀(2) . Since ₁₀(2) 0.301 , we get L₂ - 50 = 10 0.30

In the absence of the teacher, the noise level in a classroom containing 50 students is 50 dB . Assuming that each student, on average, emits the same sound energy per second, determine the noise level if the number of students increases to 100 .

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