Optics Question 579
Question: A lens of power + 2 diopters is placed in contact with a lens of power - 1 diopter. The combination will behave like
Options:
A) A convergent lens of focal length 50 cm
B) A divergent lens of focal length 100 cm
C) A convergent lens of focal length 100 cm
D) A convergent lens of focal length 200 cm
Show Answer
Answer:
Correct Answer: C
Solution:
$ \frac{1}{f}=\frac{1}{f _{1}}+\frac{1}{f _{2}}=\frac{P _{1}}{100}+\frac{P _{2}}{100}=\frac{1}{100}\Rightarrow f=100 $ cm
$ \therefore $ A convergent lens of focal length 100 cm.
