[填空题]
The sound intensity level (SIL), L, in decibewrk:: lq1y r5w,la)mgls (dB) dzo4.gastdn9ap( )d0 , of the sound intensity, I, in watts per square meter, isp4a 9).d toad n0sz(gd given by the equation
L=10log($\frac{I}{I_0}$),where $I_0$ is the reference sound intensity.
1.Two sounds have intensities $I_1$ and $I_2$ with $I_1$<$I_2$. Show that the difference
in SIL between the two sounds is L=10log($\frac{I_2}{I_1}$).
2.A train rumble has the SIL of 82 dB and a dishwasher noise has the SIL of 52 dB. Find the number of times the train rumble is more intense than the dishwasher noise.
Jack is attending a rock concert where the SIL of the music reaches 110 dB. During the concert, Jack's mom calls him to find out if he is safe and everything is going well. The SIL of his cell phone ring is 70% of the SIL of the rock music. $I_2$ = $I_1$
3.The perceived loudness of a sound doubles for every 10 dB increase in SIL.
(1)Write down the SIL of Jack's cell phone ring. L = dB
(2)Jack perceives the rock music k times as loud as his cell phone ringing. Find the value of k, giving your answer correct to 3 significant figures. K ≈
(3)Hence, decide whether Jack's mom will reach him during the concert if Jack carries his cell phone in the pocket and turned vibrating alert off.
