✔ 最佳答案
1. Your daiagram in the 1st link.
There are three complete waves in 0.9 m, hence wavelength = 0.9/3 m = 0.3 m
2. The second link:
Q3:Speed of wave = distance travelled by wave/time taken = 0.9/0.6 m/s = 1.5 m/s
Since there are 3 complete waves in a distance of 0.9 m
Wavelength = 0.9/3 m = 0.3 m
Q3: The frequency of the vibrator is 1 Hz. It means one complete wave can be produced in 1 s.
Thus, after 0.75 s, fraction of wave produced = 0.75/1 = 0.75
Therefore, 1/4 of a wave is produced after 0.75 s
The answer is option C.
2014-08-03 13:39:29 補充：
sorry, a typo in the second last sentence, it should read:
"Therefore, 3/4 of a wave is produced after 0.75 s"
2014-08-03 21:06:51 補充：
Your suppl question:
I suppose it should be question no. 4 (I typed the question no. wrongly on my post).
0.75 s is just 3/4 of the 1 s period, which corresponds to 3/4 of a complete wave.
