NEETPhysicsWaves and Sound
A wave is travelling along a string. At an instant, shape of the string is as shown in figure. At this instant, point (A ) is moving upwards. Which of the following statement(s) is/are correct?
Options
- AThe wave is travelling to the right
- BDisplacement amplitude of the wave is equal to displacement of (B ) at this instant
- CAt this instant velocity of (C ) is also directed upwards
- DPhase difference between (A ) and (C ) may be equal to ( 2 )
Correct answer
B. Displacement amplitude of the wave is equal to displacement of (B ) at this instant
Step-by-step solution
Since, (A ) is moving upwards, therefore, after an elemental time interval the wave will be as shown dotted in below figure. It means the wave is travelling leftward. Therefore, (a) 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 figure. Hence, (b) is correct. From figure, it is clear that (C ) is moving downward at this instant. Hence, (c) is wrong. The phase diffe