In a test,a subsonic jet flies overhead at an | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(A) The loudness level $L$ in decibels is given by $L = 10 \log_{10} \left( \frac{I}{I_0} \right)$.Since the sound intensity $I$ follows the inverse s

Vedclass · Accepted Answer

above $10 \, km$ from ground

Vedclass · Answer

(A) The loudness level $L$ in decibels is given by $L = 10 \log_{10} \left( \frac{I}{I_0} ight)$.Since the sound intensity $I$ follows the inverse square law,$I \propto \frac{1}{r^2}$,where $r$ is the distance (altitude).Thus,$L = 10 \log_{10} \left( \frac{k}{r^2} ight) = C - 20 \log_{10}(r)$,where $C$ is a constant.For the first case: $160 = C - 20 \log_{10}(100)$.For the second case: $120 = C - 20 \log_{10}(x)$.Subtracting the two equations: $160 - 120 = 20 \log_{10}(x) - 20 \log_{10}(100)$.$40 = 20 \log_{10} \left( \frac{x}{100} ight)$.$2 = \log_{10} \left( \frac{x}{100} ight)$.$10^2 = \frac{x}{100} \implies x = 100 	imes 100 = 10,000 \, m = 10 \, km$.Therefore,the plane should fly at an altitude of at least $10 \, km$.

In a test,a subsonic jet flies overhead at an altitude of $100 \, m$. The sound intensity level on the ground as the jet passes overhead is $160 \, dB$. At what altitude should the plane fly so that the ground noise is not greater than $120 \, dB$?

Similar Questions

How many times more intense is a $60 \ dB$ sound than a $30 \ dB$ sound?

In the musical octave 'Sa','Re','Ga',which of the following statements is correct regarding their frequencies?

The intensity level due to two waves of the same frequency in a given medium are $1 \, bel$ and $5 \, bel$. Then the ratio of amplitudes is

If the threshold of hearing is assumed to be the reference $(0 \ dB)$,then the threshold of pain is taken to be $120 \ dB$. Let the corresponding sound intensities be $I_0$ and $I$ respectively. Then $\frac{I_0}{I}$ is:

Quality (or timbre) of a sound depends on:

Vedclass Test Series

Exam Paper Generator

Online Exam Module