When a pebble falls into a pond, it pro- duces ripples on the (two-dimensional)
ID: 1602738 • Letter: W
Question
When a pebble falls into a pond, it pro- duces ripples on the (two-dimensional) water surface. The ripples spread in all directions producing a circular wavefront of increasing radius r. The amplitude of spreading ripples changes with the radius r. Assume: The energy spreading the water waves does not dissipated into the water or lost in any other way (no frictional losses). correctly describes the way the ripple ampli- tude A depends on the radius r of the circular wavefront. 1. A oc log T for some constant L 2. A oc r 4. A r2 5. A oc 6. A oc e r/L for some constant L 7. A ocExplanation / Answer
The correct option is – 9, A = constant (same for all r)
Explanation – Actually the energy carried by a wave is proportional to A2. Clearly this energy depend on the amplitude of the wave. As energy remains constant that simply means amplitude remains constant.