A simply supported beam of span 'L' carries a concentrated load 'W' at mid-span. If the width 'b' of the beam is constant and its depth is varying throughout the span, then what should be its mid-span depth, when design stress is 'f' ?-A-B-C-D--C-

C M/I = f/y. y = fI/M. y = d/2. d/2 = f*(bd^3/12)/(WL/4). 1/2 = f*(bd^2/3)/WL. d^2 = 3WL/2fb. d = sqrt[3WL/2fb].