Q. Which of the following describes the sound field propagating in a piece of steel bar stock which is being tested from one end with longitudinal waves?

• (A) Non uniform, containing maxima and minima because of the focusing effect of laterally reflected waves
• (B) Increasing to a peak, then decreasing throughout the far field
• (C) Uniformly decreasing along the length of the bar
• (D) Decreasing according to the inverse square law