During thunder light and sound are produced at the same time. But we can see the light first— Why?

Why glucose and fructose produce the same osazone?

Why can the tiger see at night?

Which ray has the same velocity as that of light-

Statement I : The velocity of light rays of different colours is the same. But the velocity of the light rays are different for any other medium. If v = velocity of light in the respective medium c = velocity of light in vacuum, mu = refractive index, then v = ( c )/(mu) . Statement II : mu is different for different media.

Estimating the following number should be interesting. The number tells you why our eye can never 'count photons', even in barely detectable light. The number of photons entering the pupil of our eye per second corresponding to the minimum intensity of white light that we humans can perceive (~10^(-10) W. m^(-2)) . Take the area of the pupil to be about 0.4 cm^(2) and the average frequency of the white light to be about 6xx10^(14) Hz.

Why can two lamps of the same type not produce interference fringe?

In a 10 m high room a partition of height 7m separates two students on either side. Both light and sound waves can deviate from their path if they experience any obstruction. Then why is it that the two students can converse with each other even if one cannot see the other?