In 1801 Giovanni Piazzi discovered the first and largest asteroid, which he named . Today, we know that the majority of the asteroids are dark bodies, that have changed little since the solar system began. These are known as type of asteroids. The second most common type of asteroid is the type. Pieces of asteroid are found on Earth and helped astronomers to predict what the spacecraft should find when it went into orbit around it. Asteroids that cross the Earth's orbit and might hit our planet are called Asteroids.

a straight line sloped

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.

snell's law

refractve index = sin incidence / sin refraction