Optics Question 926
Question: An object $ 1cm $ tall is placed $ 4cm $ infront of a mirror. In order to produce an upright image of $ 3cm $ height one needs a
[SCRA 1994]
Options:
A) Convex mirror of radius of curvature $ 12cm $
B) Concave mirror of radius of curvature $ 12cm $
C) Concave mirror of radius of curvature $ 4cm $
D) Plane mirror of height $ 12cm $
Show Answer
Answer:
Correct Answer: B
Solution:
Erect and enlarged image can produced by concave mirror. $ \frac{I}{O}=\frac{f}{f-u}\Rightarrow \frac{+\ 3}{+1}=\frac{f}{f-(-\ 4)}\Rightarrow f=-\ 6cm $
$ \Rightarrow R=2f=-12cm $
