its phase changes by $180^{\circ}$, but velocity does not change.
its phase does not change, but velocity changes.
its velocity changes and phase changes by $180^{\circ}$.
nothing can be predicted about changes in its velocity and phase.
Solution
When a traverse wave strikes a wall, it gets reflected back, the reflection causes of change in phase \(\pi\) or \(180^{\circ}\).The speed of a transverse wave remain constant in a medium.