SciencewithD

To find the value of v for different values of u in case of a concave mirror and to find the focal length. Apparatus : Optical bench,concave mirror, optical needle,a meter scale. Theory: By Mirror formula , 1/f=1/v+1/u, f=uv/(u+v), where, u = distance of object from the pole of mirror v =  distance of image from the pole of mirror    f = focal length of concave mirror Ray diagram of concave mirror Procedure:  1 Take given concave mirror and turn its reflecting surface toward a distant object to obtain image on a sheet of note book. 2 Measure the distance between mirror and image formed on the sheet. This is the rough focal length of concave mirror. 3 Clamp mirror holder in one upright and fix two optical needles in two uprights on the optical bench. Place them close to each other at one end of optical bench. Adjust their heights so that tips of the needles are at the same height as the center of the mirror. Pierce a small piece of paper into the tip of the n