Question

!Attention Please !

⭕ Class - 10th

⭕ Physics

The size of Image of An Object by a convex lens of Focal Length 20cm is observed to be reduced to 1/3rd of its size.

Find the distance of the object from the optical centre of the Lens !​

Answer 1

$\huge\mathbb{AHOY!!!}$

answer : object distance from the optical centre of the lens is 80cm.

explanation : focal length of convex lens , f = +20cm

a/c to question,

size of image = 1/3 × size of object.

so, magnification , m = -1/3

we know, magnification of lens , m = v/u

so, v/u = -1/3

so, v = -u/3 ........(1)

now applying lens maker formula,

1/v - 1/u = 1/f

or, 1/(-u/3) - 1/u = 1/20

or, -3/u - 1/u = 1/20

or, u = -80 cm

hence, object is placed 80cm from the pole of convex lens.

Answer 2

◀️◀️ QUESTION ▶️▶️

The size of Image of An Object by a convex lens of Focal Length 20cm is observed to be reduced to 1/3rd of its size.

Find the distance of the object from the optical centre of the Lens !

◀️◀️ ANSWER ▶️▶️

U= -80

ANSWER IS IN ATTACHMENT

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