If you are anchored in a fixed spot, and a set of six waves pass underneath you during a 60 second time interval, what is the wave frequency (in waves/second) of the waves?

Explanation:

Six waves passes by under 60second interval

Since it has 6 waves,

Then, it correspond to 3 wavelength

Then,

The period of each Each wavelength is 60 / 3

Then,  period = 20seconds

From the relationship between frequency and period

f = 1 / T

f = 1 / 20

f = 0.05 Hz

speed of light in vacuum is 300,000 km/s

speed of light in other mediums is given by the expression v = c/n, where c is the speed of light in vacuum and n is the refractive index of medium.

for the first medium v = 200,000 km/s

  so, refractive index of medium = 300000/200000 = 1.5

    1.5 refractive index is usually for glass. so first medium is glass.

for the second medium v = 250,00 km/s

so, refractive index of medium = 300000/250000 = 1.2

    1.2 refractive index is usually for water. so second medium is water.

for the third medium v = 0 km/s

so, refractive index of medium = 300000/0 = ∞

    ∞ refractive index is usually for opaque mediums. so third medium is opaque medium.