Optics Question 681
Question: In order to obtain a real image of magnification 2 using a converging lens of focal length 20 cm, where should an object be placed
[AFMC 2004]
Options:
A) 50 cm
B) 30 cm
C) - 50 cm
D) - 30 cm
Show Answer
Answer:
Correct Answer: D
Solution:
For real image $ m=-2 $
$ \therefore m=\frac{f}{u+f} $
$ \Rightarrow -2=\frac{f}{u+f}=\frac{20}{u+20} $
Therefore u = - 30 cm.
