Question

On hot summer days while moving in a bus the distant spot on highway appears to be wet even though it is not actually wet?



a.What physical phenomenon is responsible for this effect?

Answer 1

Highways sometimes appear wet because of heat. Highways often get hotter than the air above them after collecting heat from the sun. The heat radiates out, and warms the air just above the roadway. The hot air has a different index of refraction than the cooler air around it. This means light travels through it differently. When viewed from a low angle, a phenomenon called "total internal reflection" happens making the interface between the hotter and cooler air look like a mirror. This makes it.

Answer 2

Answer:

The Physical phenomenon which is responsible here is called "total internal reflection."

Explanation:

• Total internal reflection: If the incident ray falls on a surface with the angle of incidence greater than critical angle, then the ray will reflect back to the first medium, this incident is known as total internal reflection.
• This phenomenon occurs when light ray enters from denser to rarer medium.
• Critical angle is that angle of incidence for which the angle of refraction becomes 90°.
• Mechanism: On hot summer day the highway becomes excessive hot. The air which is in touch to the road becomes hotter than the upper atmospheric gases.

                             So the light from sun reaches to the rarer medium from denser medium ( hot air is rarer than cold air).

                            Then the incident ray crosses the critical angle and total internal reflection occurs. Due to this phenomenon the highway appears as wet.