A50-db sound wave strikes an eardrum whose area is 5.0×10−5m2. the intensity of the reference level required to determine the sound level is 1.0×10−12w/m2. 1yr=3.156×107s.

Sound Level of 50 dB is given to us

So the intensity of sound for this level of sound is given as

now we will have

by solving above equation we will have

now energy received by ear drum per second will be

Now total energy received in one year will be

so above is the energy received by year in one year

not too sure thinking it will always be directed towards the centre of the earth. could be wrong not sure

it doesn't. it was imagined up in the middle ages.