A small gremlin from Academia finds itself d =
130 cm in front of a two-lens optical system as indicated in the
figure. For light entertainment, determine the distance of the final
image (di) with respect to the second lens. cm
wrt first lens 1/v=1/f-1/u
here f=100/2=50cm
so
1/V=1/50-1/130=>v=81.25cm
now as the image due to first lens forms on the other side of the first lens at a distance 81.25cm distance between this image and second lens=81.25-50=31.25cm
focal length of second lens = -100/5 = -20cm
now 1/v = -1/20-1/31.25=>v=-12.19cm
hence the distance between the second lens and final image =12.19cm
