Question

# Two thin convex lenses of focal length f1and f2 are separated by a horizontal distance d (where d<f1,d<f2) and their centers are displaced by a vertical separation Δ as shown in figure. Taking the origin of coordinates O at the center of the first lens, the x and y coordinates of the focal point of this lens system, for a parallel beam of rays coming from the left, are given by:x=f1f2f1+f2,y=Δx=f1(f2+d)f1+f2−d,y=Δf1+f2x=f1f2+d(f1−d)f1+f2−d, y=Δ(f1−d)f1+f2−dx=f1f2+d(f1−d)f1+f2−d, y=Δ(f1−d)f1+f2−d

Solution

## The correct option is C x=f1f2+d(f1−d)f1+f2−d, y=Δ(f1−d)f1+f2−dpatiently use lens formula for individual lens one by one and get the final position of the image. The total distance would be d+v(final) and which will come as f1f2+d(f1−d)f1+f2−d. for finding y, use magnification formula and get Δ(f1−d)f1+f2−d Watch the next video for the solution.

Suggest corrections