A wave is travelling along a string. At an instant, shape of the string is as shown in fig. At this instant, point A is moving upwards. Which of the following statements is/are correct

Since A is moving upwards, therefore, after an elemental time interval the wave will be as shown dotted in following fig. It means, the wave is travelling leftward. Therefore, (1) is wrong.  Displacement amplitude of the wave means maximum possible displacement of medium particles due to propagation of the wave, which is equal to the displacement at B at the instant shown in fig. Hence (2) is correct.From figure, it is clear that C is moving downwards at this instant. Hence (3) is wrong. The phase difference between two points will be equal to π2 if distance between them is equal to λ4 Between A and C, the distance is less than λ2 It may be equal to λ4. Hence, phase difference between these two points may be equal to π2.