Question

During a sunny day, the number plate of a car travelling on the highway seems to flicker for a person walking at a distant in the opposite direction. Why?

Answer 1

The air in contact with the road is very hot, so less dense and has less refractive index comparative to air far above the road. Since, the physical conditions of the refractive medium are not stationary, so the light travelling through this medium appears to flicker and so does the image of the object flickers in our eyes.