A thin convex lens is made of two materials with refractive indices n1 and n2, as shown in figure. The radius of curvature of the left and right spherical surfaces are equal. f is the focal length of the lens when n1=n2=n. The focal length is f+Δf when n1=n and n2=n+Δn. Assuming Δn<<(n−1) and (1<n<2), the correct statement(s) is/are?
This question has multiple correct options
If nΔn<0, then fΔf>0
For n=1.5,Δn=10−3 and f=20cm, the value of ∣Δf∣ will be 0.02cm(round off to 2nd decimal place)
The relation between fΔf and nΔn remains unchanged if both the convex surfaces are replaced by concave surfaces of the same radius of curvature