Question

4. Two lens of power + 6D and -2 D are placed in
contact. Find the power and focal length of the
combination.​

Answer 1

Answer:

P = +4D    f = 25 cm

Explanation:

We know,

P = P1 + P2

P = +6D + (-2D)

P = +4D

We know,

f = 1/P

f = 100/4 cm

f = 25 cm