(a) Suppose you hear a thunder clap 15.2 seconds after seeing the associated lightning flash. Take the speed of sound in air to be 343ms-1 and the speed of light to be 3 × 108 ms-1. How far are you from the observed lightning strike?

(b) Find the speed of sound in mercury given that the bulk modulus is 2.8×1010 Nm-2 and a density of 13600 kg m-2.

(c) Show that the difference in decibel levels, β1 and β2 of a sound source is related to the ratio of its distances r1 and r2 from the receivers by ⎟⎠⎞⎜⎝⎛=−=⎟⎟⎠⎞⎜⎜⎝⎛=−BALogLogBLogArPIrrand4Uselog2022112πββ