Question

An object is 0.09m from a convex lens and the image is formed 36cm on the same side of the
lens. The magnification produced is:​

Answer 1

Given:

Distance of the object from the convex lens = 0.09 m = 9 cm

Distance of the image from the convex lens = 36 cm

To find:

The magnification produced.

Solution:

The formula for magnification is : Distance of image/ distance of the object.

Since the image is formed on the same side therefore the distance of image will be in negative, also the object is in the opposite side of the light waves travelling to the lens, therefore it will also be negative.

Magnification = -36/ -9 = 4

Therefore the magnification of the image is 4.

Answer 2

Given:

An object is 0.09m from a convex lens and the image is formed 36cm on the same side of the

lens.

To find:

Magnification produced ?

Calculation:

Magnification of a lens is defined as the ratio of image distance to the object distance.

$\sf \therefore \: magnification = \dfrac{image \: distance}{object \: distance}$

$\sf \implies \: magnification = \dfrac{-36 \: cm}{ - 0.09 \: m}$

$\sf \implies \: magnification = \dfrac{-36 \: cm}{ - 0.09 \times 100 \: cm}$

$\sf \implies \: magnification = \dfrac{-36 \: cm}{ - 9 \: cm}$

$\sf \implies \: magnification = 4$

• Magnification = 4 signifies that the image is virtual, erect and larger than the object dimension.

• Also, sign of "object distance" is negative, because it has been put on the left side of the lens (as per coordinate geometry).

• Since the question tells that the image is produced on the same side of the object, hence image distance will also be taken as negative.