Saved Bookmarks
| 1. |
Deviation of a ray incident on a converging lens Find the point at which the first ray crosses the principal axis after refraction (Fig. 34-39). Also find its deviation. |
Answer» Solution :We can see that the two refracted rays will meet at a POINT in the focal PLANE. Since the ray passing through the  Optical center will pass undeviated, we can say that this meeting occurs at an angle of `theta` and hence at a distance `ftheta` below the focus Calculation : By the property of the similar triangles, we can say that `(h)/(X)=(ftheta)/(f-x)=phi`. Solving, we GET `x=(hf)/(h+ftheta)` and `phi=(h+ftheta)/(f)`.  THEREFORE, the deviation is `theta-phi=(h)/(f)` |
|