[单选题]
For a wave traveling in a mediu
q+pg gg39wx) l 2 pjknwl)/pq9m, t
da-jf2.m 5r wghe variation of the particles' displacement with distance travelled is shown in the following graphs, which represent the wave at different m
-mr2.d gfj5 waoments in time of a wave travelling to the right.
Graph I shows the wave at t=0s, while graph II is at t=1s.
The time difference between the two graphs is less than the wave's period.
Graph I
Graph II
What is the wave speed?