Optics Question 582
Question: Two lenses of power +12 and - 2 diopters are placed in contact. What will the focal length of combination
[MP PET 1990; MNR 1987; MH CET (Med.) 2001; UPSEAT 2000; Pb. PMT 2003]
Options:
A) 10 cm
B) 12.5 cm
C) 16.6 cm
D) 8.33 cm
Show Answer
Answer:
Correct Answer: A
Solution:
Power of the combination $ P=P _{1}+P _{2} $
$ =12-2=10D $
Focal length of the combination $ F=\frac{100}{P}=\frac{100}{10}=10cm $
