Four students differentiated between 2 celestial terms. Which student's example is NOT true?
1."A comet is mainly composed of ice and dust, and a meteoroid is composed of debris of comets and sometimes debris of asteroids."
2."A comet can generate a tail of gas and dust, and a meteor has a bright tail of light caused by a meteoroid during its atmospheric flight."
3."A moon is a celestial body that makes an orbit around a planet, and an asteroid orbits the sun."
4."A meteoroid is the part of a meteorite that survives the passage through our atmosphere and reaches the Earth's surface; and a meteorite is similar to an asteroid, but smaller."

igneous rocks also form where plates converge. the subducting plate melts as it sinks into the crust of the earth, and the melt rises into the overriding plate forming volcanoes. metamorphic rocks are formed mainly in the lithosphere, wherever there is high pressure and high temperature. -woods

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.