Optics Question 935
Question: An object 2.5 cm high is placed at a distance of 10 cm from a concave mirror of radius of curvature 30 cm The size of the image is
[BVP 2003]
Options:
A) 9.2 cm
B) 10.5 cm
C) 5.6 cm
D) 7.5 cm
Show Answer
Answer:
Correct Answer: D
Solution:
$ R=-30cm\Rightarrow f=-15cm $
$ O=+2.5cm, $
$ u=-10cm $ By mirror formula $ \frac{1}{-15}=\frac{1}{v}+\frac{1}{(-10)}\Rightarrow v=30cm. $ .
Also $ \frac{I}{O}=-\frac{v}{u}\Rightarrow \frac{I}{(+2.5)}=-\frac{30}{(-10)} $
$ \Rightarrow I=+7.5cm. $
