One student designed an experiment to demonstrate the formation of a geologic feature. the steps of the experiment are listed below.

1. place a rectangular piece of cardboard on a table.
2. take a two inches long rigid broom straw.
3. place the straw on the cardboard along one of its edges.
4. use a clip to attach the middle of the straw to the cardboard so that approximately half of the straw is on each side of the clip.
5. place one hand on each of the two halves of the straw.
6. push both ends of the straw towards the clip.
7. observe the straw snap as it moves up and bends due to pressure.

which of these geologic features was created by the process demonstrated by the student's experiment?

a. the aleutians islands
b. the big island of hawaii
c. the grand canyon
d. the sierra nevada mountains

good for her? ? where is the question?

electromagnetic shielding is the practice of reducing the electromagnetic field in a space by blocking the field with barriers made of conductive or magnetic materials. shielding is typically applied to enclosures to isolate electrical devices from their surroundings, and to cables to isolate wires from the environment through which the cable runs. electromagnetic shielding that blocks radio frequency electromagnetic radiation is also known as rf shielding.

the shielding can reduce the coupling of radio waves, electromagnetic fields and electrostatic fields. a conductive enclosure used to block electrostatic fields is also known as a faraday cage. the amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of apertures in a shield to an incident electromagnetic

from wikipedia

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.