Question

A small pulse travelling with speed $v$ in a string is shown at $t=0$, moving towards free end. Select the shape of string from column-II at moments shown in column-I

Answer 1

A) At $t=\frac{L}{v}$ The wave will come back to the starting point and since it is moving away from free end so it will get inverted. So Image 3 is should be right answer.

B) At $t=\frac{2L}{v}$ the wave will back to the same place directed towards free end and it will not get inverted at the fixed end while it will get inverted at the free end. So answer should be 4.

C) At $t=\frac{3L}{v}$, the wave will be at the open end and travel towards fixed end and it will get inverted with respect to image 4. So image 1 is the answer.