Question

| 18. Two identical equiconvex lenses of refractive
1
index % and focal length 16cm are kept in
contact. The space between the lenses is filled
with water of refractive index %. What is the
focal length of the combination? (4
? (দুখন সমজাতীয়​

Answer 1

Answer:

Water in between the lens can be considered to be a concave lens of refractive index of water as shown in the figure. This suggests that the radius of curvature of all the lenses is same.