A layer of atmosphere whose temperature is less than the other layer behaves as optically________.

A layer of the atmosphere whose temperature is less than the other layer behaves as an optically denser medium.
Temperature between the layers of the atmosphere also determines the extent of bending of light in that medium. Air expands on receiving heat which results in increasing volume. The molecules in the hotter layer stay scattered. The layer of cold air in the atmosphere acts as an optically denser layer than hot air because the molecules are closely connected and cause more refraction.