For example, H-Cl has a dipole. The electrons spend more of their time near the Cl atom (the red end in the diagram below). A dipole-dipole interaction is the attraction between two polar molecules. When they approach each other, the negative end one molecule attracts the positive end of the other.
Eyes sensitive to light can also be caused by viruses or inflammation, such as those found in sinus infections. If you have a cough, aching jaw, blocked nose, headaches and lethargy then it's best to visit your GP for a diagnosis of a possible sinus infection and simple antibiotic treatment.
The retinas of our eyes have a large number of light-sensitive cells. These cells are of two types. One type of cell is cone shaped, while the other type is rod shaped. They are called cones and rods respectively. The rods respond to intensity or brightness of light, while the cones respond to colours. The cones make it possible to distinguish between different colours.