Question

combination of power of lens​

Answer 1

Answer:

The power of a convex lens is positive and that of a concave lens is negative. Thus a convex lens of focal length 40 cm is said to possess a power of + 2.5 dioptre. ... Thus the power of combination of lenses is the algebraic sum of the powers of individual lenses.

If the lenses of focal lengths f1 and f2are “thin”, the combined focal length f of the lenses is given by 1f=1f1+1f2 1 f = 1 f 1 + 1 f 2 while if the lenses are separated by some distance d then the combined focal length is given by 1f=1f1+1f2−df1f2 1 f = 1 f 1 + 1 f 2 − d f 1 f 2 .

Hope it's helpful...☺️

Answer 2

Answer:

The power of a convex lens is positive and that of a concave lens is negative. Thus a convex lens of focal length 40 cm is said to possess a power of + 2.5 dioptre. ... Thus the power of combination of lenses is the algebraic sum of the powers of individual lenses.