Consider a string of total length l, made up of three segments of equal length. the mass per unit length of the first segment is μ, that of the second is 2μ, and that of the third μ/4. the third segment is tied to a wall, and the string is stretched by a force of magnitude ts applied to the first segment; ts is much greater than the total weight of the string. how long will it take a transverse wave to propagate from one end of the string to the other? express the time t in terms of l, μ, and ts.

Explanation:

Length of each segment is

Speed of wave in first segment is

Speed of wave in second segment is

Speed of wave in third segment is

Now time for the transverse wave to propagate is

simplifying we get

as we know our atmosphere or air have different levels. every level has other gasses, and every gas has another permeability. when the light comes from lower permeability to higher permeability, it changes its direction. so that means that when the light comes from the moon to the earth, it changes it's direction many more times. it basically means that the shape of the light part of the moon is changed on the earth.

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