Saved Bookmarks
| 1. |
Draw a ray diagram to show how the image is formed when the object is placed between/and 2/distances from a convex lens. Deduce the relation between the distances of the object and the image from the lens and the focal length of the lens under this condition. |
Answer» SOLUTION :The RAY diagram is shown in FIG. 9.65. The image A.B. is real, inverted and magnified one. As `triangleA.B.C`and `triangleABC`are similar, HENCE `(A.B.)/(AB) = (CB.)/(CB)`…….(i) Again as `triangleA.B.F` and `triangleALCF` are similar, hence `(CB.)/(CB) = (B.F)/(CF) = (CB. - CF)/(CF)` As per sign conventions used, `CB =-u, CB. = +v` and `CF = +f` `therefore v/(-u) = (v-f)/f` or `vf =-uv + uf` Dividing both sides by uvf, we get `1/u = -1/f + 1/v` or `1/v - 1/u = 1/f` |
|