If you are using eye glasses of power 2 D, your near point is

For a combination of two convex lenses of focal lengths $f_1$ and $f_2$ to act as a glass slab, the distance of separation between them is

If a ray of light passes through an equilateral prism such that the angle of incidence and the angle of emergence are both equal to $70 \%$ of the angle of the prism, then the angle of minimum deviation is

The focal lengths of the objective and the eyepiece of a compound microscope are 2 cm and 3 cm respectively and the distance between them is 15 cm . The final image formed by the eyepiece is at infinity. The distances of the object and the image produced by the object from the objective lens are respectively.