(a) In the figure shown a slab of refractive index `(3)/(2)` is moved toward a stationary observer with speed `6 cm//s` . `A` point `O` is observed by the observer with the help of paraxial rays through the slab. Both `O` and observer lie in are. Find the velocity (in `cm//s`) with which the image will appear to move to observer.

(b) in the previous question if the object moves towards rigth with a velocity of `6 cm//s` and find the velocity of the final image (in `cm//s`) as seen by observer :

Answer

(a)0,(b)6

Explanation

(a) The final image formed by slab has a fixed separation form `'O'` .
Shift produced is `t` `(1-(1)/(3//2))=(t)/(3)` where `'t'` is thickness which is constant. The shift produced in the position of the image `w.r`. to `O` is fixed
`therefore` velocity of final image is zero `w.r.` to `O`
(b) Velocity of the final image = velocity of object `=6cm//s Ans` .