PHY-102:Wave, Sound, and Light Exercises
Complete the following exercises.
1. What is the source of all waves?
Source of all wave motion is a disturbance in a matter or a vibration
2. A water wave vibrates up and down four times each second, the distance between
two successive crests is 5 meters, and the height from the lowest part to the highest
part of the wave is 2 meters.
a. What is the frequency of the wave in hertz?
Frequency = 4 Hz
b. What is the period of the wave in seconds?
Period = 1/frequency = ¼ = 0.25 seconds
c. What is the speed of the wave in meters per seconds?
Speed = wavelength*frequency = 5*4 = 20 m/s
d. What is the amplitude of the wave in
meters? Amplitude = ½ *2m =1m
3. When you sit in the stands at a baseball stadium, you will hear the crack of the bat
a short time after you see the batter hit the ball. Explain.
Light travels faster (3.0*10^8m/sec) than sound (340m/sec). Therefore, we
can see the crack of the batter faster than the sound since the light reaches our
eyes quicker than the sound reaches our ears.
4. Why is the moon sometimes described as silent?
Because it has no atmosphere/air which is the main medium to transport sound
waves.
5. You are hiking in a canyon and you notice an echo. You decide to let put a yell and
notice it took 2 seconds before you heard the echo of your yell. How far away is
the canyon wall that reflected your yell?
, Solomon 2
Speed of sound is 340m/s
Time for the echo is 2sec
Let h = distance of the canyon wall