A student is standing 8 m from a roaring truck engine that is measured at 100 dB. The student moves 4 m closer to the engine. What is the measured loudness at the new distance?

The loudness or sound intensity of the roaring truck engine is inversely proportional to the square of the distance. it follows the law of squares that is

r1^2 / r2^2 = L2/L1

8^2 / 4^2 = L2 / 100 dB

L2 = 400 dB

The answer to this problem is 400 dB increased frim 100 dB.