Read the excerpt from "Street Cleaning Day." An open space on the street snapped him out of his thoughts and back to the wheel. He sped up a little and moved close to the curb, pulling ahead of the space. Just as he shifted his car in reverse, a flash swooped in from behind and took from Square what the morning had offered. How is this excerpt important to the poem as a whole? A. It shows the exposition. B. It introduces the main characters. C. It shows the falling action. D. It introduces the conflict. Don't answer that! But ad me on snap

convex lenses are thicker at the middle. rays of light that pass through the lens are brought closer together (they converge). a convex lens is a converging lens. when parallel rays of light pass through a convex lens the refracted rays converge at one point called the principal focus.

the answer is 3.1 his answer is wrong mines is right

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.