Question 345: Ray Optics

Question

A convex lens and a concave lens, each having same focal length of 25 cm, are put in contact to form a combination of lenses. The power in diopters of the combination is

Accepted Answer

Power of combination in dioptres
P = P
1
+ P
2
= $${{100} \over {{f_1}}}$$ + $${{100} \over {{f_2}}}$$
= $${{100} \over {25}} - {{100} \over {25}}$$ = 0

Answer

zero

Answer

25

Answer

50

Answer

infinite.

Ray Optics

A convex lens and a concave lens, each having same focal length of 25 cm, are put in contact to form a combination of lenses. The power in diopters of the combination is

Choose the correct answer: