Optics Question 93
Question: The object distance u, the image distance v and the magnification m in a lens follow certain linear relations. These are
[Roorkee 2000]
Options:
A) $ \frac{1}{u}\text{ versus }\frac{1}{v} $
B) m versus u
C) u versus v
D) m versus v
Show Answer
Answer:
Correct Answer: A
Solution:
For a lens $ \frac{1}{f}=\frac{1}{v}-\frac{1}{u} $
$ \Rightarrow \frac{1}{v}=\frac{1}{u}+\frac{1}{f} $ …..(i)
Also $ m=\frac{f-v}{f}=1-\frac{v}{f} $
$ \Rightarrow m=( -\frac{1}{f} )\ v+1 $ ….(ii)
On comparing equations (i) and (ii) with $ y=mx+c. $
It is clear that relationship between $ \frac{1}{v} $ vs $ \frac{1}{u} $ and m vs v is linear.
