Question

A convex lens of focal length 15 cm forms a real image at a distance of 20 cm from its optical centre. Find the position of the object. Is the image formed by the lens magnified or diminished ? 5​

Answer 1

Answer:

The required answer for the question is -60 cm .

Answer 2

A convex lens of focal length 15 cm forms a real image at a distance of 20 cm from its optical centre. Find the position of the object. Is the image formed by the lens magnified or diminished ?

Given data,

f=15cm

v=30cm

h=−5cm

u=?

⇒  f/ 1  =  v /1  −  u/ 1

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⇒  u /1  =  v/ 1  −  f/ 1

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=  1/30  −1/  15  

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 =   1−2/30

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=  −1/30

⇒u=−30cm

Also we know that,

m=  +v/u

   =   h  ′/h

⇒  −30/30

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=  h /−5

⇒h=+5

∴object height=5cm

 

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