Engineering Board Exam Reviewer · Physics · medium
Two thin lenses with focal lengths of +20 cm and −50 cm are placed in contact. What is the power of the combination?
- +7 diopters
- +3 diopters
- −3 diopters
- +30 diopters
Answer
B. +3 diopters
Solution
P = P1 + P2 = 1/0.2 + 1/(-0.5) = 5 - 2 = +3 D.
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