(C) The magnification $m$ is given by $m = \frac{f}{f + u}$.For a virtual image,$m = +3$ and $u = -8 \ cm$. Substituting these values: $3 = \frac{f}{f

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(C) The magnification $m$ is given by $m = \frac{f}{f + u}$.For a virtual image,$m = +3$ and $u = -8 \ cm$. Substituting these values: $3 = \frac{f}{f - 8} \implies 3f - 24 = f \implies 2f = 24 \implies f = 12 \ cm$.For a real image,$m = -3$ and $u = -16 \ cm$. Substituting these values: $-3 = \frac{f}{f - 16} \implies -3f + 48 = f \implies 4f = 48 \implies f = 12 \ cm$.Since $f = 12 \ cm$,it lies between $8 \ cm$ and $16 \ cm$.

Class 12 Physics Ray Optics and Optical Instruments Refraction by Lenses

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An object has an image thrice of its original size when kept at $8 \ cm$ and $16 \ cm$ from a convex lens. The focal length of the lens is:

A
$8 \ cm$
B
$16 \ cm$
C
Between $8 \ cm$ and $16 \ cm$
D
Less than $8 \ cm$

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Class 12

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Ray Optics and Optical Instruments

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Refraction by Lenses

$A$ convex lens is made of three different materials as shown in the figure. How many images will be formed for a point object placed on its principal axis?

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An object is placed at a distance of $4\,cm$ in front of a concave lens of focal length $12\,cm$. The nature and position of the image from the lens is

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$A$ lens which has a focal length of $4 \; cm$ and a refractive index of $1.4$ is immersed in a liquid of refractive index $1.6$. What will be the new focal length in $cm$?

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$A$ magnifying lens has a focal length of $10 \, cm$. If the image is formed at a distance of $30 \, cm$ from the lens,what is the magnification?

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An object has an image thrice of its original size when kept at $8 \ cm$ and $16 \ cm$ from a convex lens. The focal length of the lens is:

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