Question 45

[tnfifn3735]

Is my reasoning correct for this question? I said that if the sound measured was 100 and 90 then the first sound would be 10 times greater. Since 93 is between 90 and 100 the answer should be between 1 and 10. The only answer is C. Is this correct?

Thanks.

[jellywing_2058]

Using your reasoning you can eliminate the answer choices that are values above 10; this is correct and leaves you with answer choices C and D. As shown in the explanation, you need to do:

dB = 10 log (I/Io)
I/Io = 10^(dB/10)

Therefore, if I/Io was equal to 1 (I=Io) then the difference between the two dB values would be zero, which is not the case here (90 and 93 dB). This means the answer must be >1 and <10.