An object 2 cm high is placed at a distance of 16 cm from mirror that produces a real image 3 cm high. (a) Find the position of the image (b) What is the focal length of the mirror?

Asked by Topperlearning User | 2nd May, 2014, 01:32: PM

Expert Answer:

(a) Position of object, height of object and image are 16 cm, 2 cm and 3 cm respectively.

m = h'/h   

 

In this, height of image will be taken negative as it is a real image.

So,

m = -3/2 = -1.5,

Also, m = -v/u

Therefore, -1.5 = -v/(u)

v = -1.5 x 16 = -24 cm

 

(b) Focal length

u = -16 cm, v = -24 cm, focal length, f = ?

1/v+1/u = 1/f  

 

-1/24 + (-1/16) = 1/f

-5/48 = 1/f

f = -9.6 cm

Answered by  | 2nd May, 2014, 03:32: PM

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