There are 5 syllables. Trans-mis-siv-i-ty.

The answer depends on the transmissivity of the material.

As long as the transmissivity is the measure of how easily water moves through the porous media along the joint length so it can be calculated as :

length/sec *length=m^2 /sec

Light like water follows the path of least resistance, although light can also be refracted at a better rate. To limit the flow of light one would need to filter that light and use only the spectrum needed for transmissivity. Although light will still travel at normal speed.

The question, as posed, makes little sense. All that they would find is the points of intersection of the circles!

The question says nothing about the sizes of the circles - whether they are the same or whether they represent some measure of seismic transmissivity of the earth near (under) them.