Problem 10.8. Find the distance at which an object should be placed in front of a convex lens of focal length 10 cm to obtain an image of double its size?
Data
Focal length of lensf=10cm
Image size =2× object size
K/a magnificent m =2
To find....
Object distance?
Solution
Magnification is given by M =q/p
2=q/p. Q = 2p. But two object distance is given by.
1/f =1/p + 1/q
For real image =1/10/=1/p +1/2p. = 2+1/2p. 3/2
2p=30. P= 15cm answer
For virtual image q=2p = 1/10 =1/p +1/ -2p. 2- 1/2p =1/2p
2p.= 10 p=5cm. Answer
