Question

A diverging lens has a focal length of 14.0 cm. Locate the images for each of the following object distances. For each case, state whether the image is real or virtual and upright or inverted, and find the magnification. (a) 28.0 cm q = cm (b) 14.0 cm q = cm

Answer 1

Focal length (f)   = 14.0 cm

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(a)     If Object distance (u) = 28.0 cm

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         FromLens makers formula :

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          1/ f    = 1 / u + 1 / v

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   or    1 / v   = 1/ f   - 1 / u  

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                   = 1 / 14.0 - 1 / 28.0

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   or      v     = 28 cm

Magnification m = -v/u = -28 / 28 = -1

Image is real and inverted.

(b)   u = 14.0 cm

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Hence   1/ v   = 1 /f    - 1 / u

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                     = 1 / 14 - 1 / 14

       or     v = 0 cm

Magnification m = -v/u

=-0/14 = 0

Image is virtual and upright .

I hope help you !!