At the same distance the noise of a sandblaster is 13 dB louder than a power drill. This means the the displacement amplitude of the sound waves from the sandblaster is how many times greater than that of the power drill if both sounds have the same frequency?

Answer 1

20*Log(Ns/Np) = 13.
Log(Ns/Np) = 13/20 = 0.65,
Ns/Np = 10^0.65 = 4.47.
Ns = 4.47Np.