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प्रश्न
A divergent lens of focal length 30 cm forms the image of an object of size 6 cm on the same side as the object at a distance of 15 cm from its optical centre. Use lens formula to determine the distance of the object from the lens and the size of the image formed.
उत्तर
Given:
f = −20 cm (It is a diverging lens.)
v = −15 cm (Image is formed on the same side of the lens.)
Using the lens formula,
`1/f=1/v+1/u`
`->1/u=1/v+1/f`
`=1/((-15))+1/((-30))=-1/30`
∴u = 30 cm
Given: Height of the object, h = 6 cm
Height of the image, h' = ?
Magnification,` m=v/u=(h')/h`
∴ `(h')=hv/u=6xx((-15))/((-30))`
∴ h' = 3 cm
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संबंधित प्रश्न
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(A) 20 cm on the other side of the lens and is of the same size, real and erect.
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(C) 20 cm on the other side of the lens and is of the same size, real and inverted.
(D) 20 cm on the other side of the lens and is of the same size, virtual and erect.
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