A sinusoidal longitudinal wave is travelling in positive `x` direction. Wave length of the wave is `0.5 m` At time `t = 0`, the change in pressure at various points on the `x` axis can be represented as shown in figure. Consider five particles of the medium A, B, C, D and E whose `x` co-ordinates are `0.125 m, 0.1875 m, 0.250 m, 0.375 m` and `0.50 m` respectively.
(a) Which of the above mentioned five particles of the medium are moving in positive x direction at `t = 0`.
(b) Find the ratio of speed of particles B and D at `t = 0`.

Answer

(a) A and B
(b) `1/sqrt(2)`