Question

The sound of a jet engine is given as 120 dB. What is the intensity of the jet sound wave?
a-1.0 W/m2
b-0.8 W/m2
c-0.6 W/m2
d-0.4 W/m2
e-0.2 W/m2

Answer 1

Answer:

We know that the formulae of decibel dB = 10log( I / I1 ) .

Here I1 is  10-^12 W /m^2   we get it from the question.

And the  I is the intensity of the sound wave in the medium.  

As the the decibel is given as 12dB.

Hence, 120 = 10log(I / I1)  

10^12 = I / I1.

So, on solving we get I = 1 watt.