Which form of vitamin a enables the eye to react to changes in light?

Abeam of electrons with of wavelength of 7.5 x 10-6 m is incident on a pair of narrow rectangular slits separated by 0.75 mm. the resulting interference pattern is projected onto a screen 10.0 m from the slits. what is the separation of the interference maxima in the resulting interference pattern?

What is relative velocity? in which condition is relative velocity known by adding the velocity of the first body and that of the second body

Which accurately compares concave and convex lenses?