2.
A point source of light O of single colour is seen through a rectangular glass slab PORS. The paths of two rays, in and outside the slab, are shown in Fig. 4.39.(attachment)
(i) In the diagram, label the position I of the
source O where it will appear when seen
through the surface RS.
(ii) Does the source O appear to be nearer or farther with respect to the surface PQ ?
(iii) How does the shift depend on the thickness PS or QR of the slab ?
(iv) Justify your answer in (ii) with the help of an appropriate ray diagram.
(v) For the same rectangular glass slab, which colour from the visible spectra (violet to red) will produce the maximum shift?
Hoping for well defined answers.
Answers
(i) The source O appears to be nearer with respect to the surface PQ when viewed through the surface RS.
(ii) The shift decreases with the decrease in thickness PS or QR of the block.
(iii) The ray diagram is shown in the figure in which for the thickness PS, the image is at I, while the thickness PS' ('. Now the shift is OI'which is less than the shift OI for the thickness PS of the block.
(iv) The same rectangular glass block will produce maximum shift for the violet light incident on it for which the refractive index of glass is most.
Answer:
(i) The source O appears to be nearer with respect to the surface PQ when viewed through the surface RS.
(ii) The shift decreases with the decrease in thickness PS or QR of the block.
(iii) The ray diagram is shown in the figure in which for the thickness PS, the image is at I, while the thickness PS' ('. Now the shift is OI'which is less than the shift OI for the thickness PS of the block.
(iv) The same rectangular glass block will produce maximum shift for the violet light incident on it for which the refractive index of glass is most.