(D) For a convex lens,magnification $m = \frac{f}{f+u}$.Given $f = 20 \ cm$ and $|m| = 2$.Case $1$: Real image,$m = -2$.$-2 = \frac{20}{20 + x_1} \imp

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(D) For a convex lens,magnification $m = \frac{f}{f+u}$.Given $f = 20 \ cm$ and $|m| = 2$.Case $1$: Real image,$m = -2$.$-2 = \frac{20}{20 + x_1} \implies -40 - 2x_1 = 20 \implies -2x_1 = 60 \implies x_1 = 30 \ cm$.Case $2$: Virtual image,$m = +2$.$2 = \frac{20}{20 + x_2} \implies 40 + 2x_2 = 20 \implies 2x_2 = -20 \implies x_2 = 10 \ cm$.Thus,the ratio $\frac{x_1}{x_2} = \frac{30}{10} = 3:1$.

Class 12 Physics Ray Optics and Optical Instruments Refraction by Lenses

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$A$ convex lens of focal length $20 \ cm$ produces images of the same magnification $2$ when an object is kept at two distances $x_1$ and $x_2$ $(x_1 > x_2)$ from the lens. The ratio of $x_1$ and $x_2$ is

JEE MAIN 2019 All JEE MAIN

A
$5 : 3$
B
$2 : 1$
C
$4 : 3$
D
$3 : 1$

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Ray Optics and Optical Instruments

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Refraction by Lenses

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$A$ convex lens of focal length $20 \ cm$ produces images of the same magnification $2$ when an object is kept at two distances $x_1$ and $x_2$ $(x_1 > x_2)$ from the lens. The ratio of $x_1$ and $x_2$ is

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