(a) If the distance from the point sound source triples, the sound intensity will be : (i) 3 (ii) 1//3 (iii) 1//9. times the original value. Why ?
(b) By how much must the distance from the point source be increased to reduce the sound intensity by half ?

Explanation

(a) (iv) `1//9`, becomes sound intensity, `I` is inversely proportional to the square of distance (r) Tripling `r` will reduce `I` to `I//9`.
(b) As `I prop (1)/(r^2)`, In becomes `I' (= I//2)` if `r'^2` becomes `2 r^2` i.e., r' becomes `sqrt(2 r^2) = 1.4 r`.