There is an interesting optical effect you have likely noticed while driving along a flat stretch of road on a sunny day. A small, distant dip in the road appears to be filled with water. You may even see the reflection of an oncoming car. But, as you get closer, you find no puddle of water after all;the shimmering surface vanishes, and you see nothing but empty road. It was only a mirage, the name for this phenomenon. The mirage is due to the different index of refraction of hot and cool air. The actual bending of the light rays that produces the mirage is subtle, but we can make a simple model as follows. When air is heated, its density decreases and so does its index of refraction. Consequently, a pocket of hot air in a dip in a road has a lower index of refraction than the cooler air above it. Incident light rays with large angles of incidence (that is, nearly parallel to the road, as shown) experience total internal reflection. The mirage that you see is due to thisreflection. As you get nearer, the angle goes below the critical angle and there is no more total internal reflection; the “water” disappears! The pocket of hot air appears to be a pool of water becauseA. Light reflects at the boundary between the hot and cool air.B. Its density is close to that of water.C. Light refracts at the boundary between the hot and cool air.D. The hot air emits blue light that is the same color as the daytime sky.
Applications Of Reflection Of Light
When a light ray (termed as the incident ray) hits a surface and bounces back (forms a reflected ray), the process of reflection of light has taken place.
Sign Convention for Mirrors
A mirror is made of glass that is coated with a metal amalgam on one side due to which the light ray incident on the surface undergoes reflection and not refraction.
There is an interesting optical effect you have likely noticed while driving along a flat stretch of road on a sunny day. A small, distant dip in the road appears to be filled with water. You may even see the reflection of an oncoming car. But, as you get closer, you find no puddle of water after all;
the shimmering surface vanishes, and you see nothing but empty road. It was only a mirage, the name for this phenomenon. The mirage is due to the different index of refraction of hot and cool air. The actual bending of the light rays that produces the mirage is subtle, but we can make a simple model as follows. When air is heated, its density decreases and so does its index of refraction. Consequently, a pocket of hot air in a dip in a road has a lower index of refraction than the cooler air above it. Incident light rays with large angles of incidence (that is, nearly parallel to the road, as shown) experience total internal reflection. The mirage that you see is due to this
reflection. As you get nearer, the angle goes below the critical angle and there is no more total internal reflection; the “water” disappears!
The pocket of hot air appears to be a pool of water because
A. Light reflects at the boundary between the hot and cool air.
B. Its density is close to that of water.
C. Light refracts at the boundary between the hot and cool air.
D. The hot air emits blue light that is the same color as the daytime sky.
Trending now
This is a popular solution!
Step by step
Solved in 2 steps
