[填空题]
The sound intensity level, D, i6omcza60v z)dzv o*gj0 smc 1)n decibels (dB), e--b bbfh3dq95:gavucan be modelled by the function
v 9af-bbe3-bdq :5 uhg D(I)=10$log_{10}$(I)+120,I≥0,
where I is the sound intensity, in watts per square meter (W /$m^2$).
1.A vacuum cleaner has a sound intensity of 1.6$\times10^{−5}$ W /$m^2$. Calculate the intensity level of the vacuum cleaner. D = dB
2.A fire truck siren has an intensity level of 124 dB. Find the sound intensity of the siren. I ≈ W /$m^2$