Question

Suppose the image of an object is upright and magnified 1.79 times when the object is placed 17.4 cm from a lens. Find the location of the image and the focal length of the lens.

q=___cm

f=___cm

Answer 1

Here ,

magnification ,m = - 1.79

object distance , do = 17.4 cm

let the image distance is q

magnification = -q/do

-1.79 = -q/17.4

q = 31.15 cm

the image is located at 31.15 cm

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let the focal length is f

Using lens formula

1/f= 1/di +1/do

1/f = 1/31.15 + 1/17.4

f = 11.16 cm

the focal length of the lens is 11.16 cm