How many times is a ray of light reflected by 2 plane mirrors placed parallel and facing each other

the ray is reflected infinite number of times by 2 plane mirrors placed parallel to each other as each reflected ray would be the incident ray for the other.

Explanation:

the ray is reflected infinite number of times by 2 plane mirrors placed parallel to each other as each reflected ray would be the incident ray for the other.

Placing one mirror at an angle causes reflections to curve.

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.