Answer:

Explanation:
Given that,
The frequency of local AM radio station, f = 696 KHz = 696000 Hz
We need to find the energy of the frequency at which it is broadcasting.
We know that,
Energy of a wave, E = hf
Where
h is Planck's constant
Put all the values,

So, the energy of the wave is equal to
.
Crates is the correct answer because they create dents that make the bumps of mountains.
Answer:
Echoes are the reflection of sound from relatively flat object that is far enough away that you can discern the time difference. Echoes are used to measure distance, velocity, and the shape of objects. Echoes off gratings result in an unusual pinging sound