The refractive index n of glass depends on the color (wavelength) of the light passing through it. The most common optical glass, Borosilicate BK7, is characterized at wavelength 486.1 nm (blue, designated with letter F) -> nF=1.52238, and at wavelength 656.3 nm (red, designated with letter C) -> nC=1.51432. Two beams (one of each wavelength) are prepared to coincide, and enter the flat polished surface of a BK7 block at the same point, at angle of 30 arc degree measured from the normal to the surface. What is the angle between the blue beam and the red beam in the glass block?
What will be the distance between the lens and the image if the object is placed at the focal distance from the lens?