#### Question

A convex lens of focal length 0.10 m is used to form a magnified image of an object of height 5 mm placed at a distance of 0.08 m from the lens. Calculate the position, nature and size of the image.

#### Solution

Given:

Focal length, f = 0.10 m = 10 cm

Object distance, u =-0.08 m =-8 cm

Height of the object, h = 5 mm = 0.5 cm

Applying lens formula, we get:

1/v-1/u = 1/f

or, 1/v = 1/f + 1/u

or, 1/v = 1/10 + 1/(-8)

Image distance, v =-80/2 =-40 cm

or, v =-0.40 m

Thus, the position of image is 0.40 m from the lens on the same side as the object (on the left of lens).

Magnification, m = h'/h = v/u

m = h'/0.5 = (-40)/(-8) = + 5

or, size or height of image, h' = 2.5 cm or 25 mm

Further, the value of magnification is positive; therefore, the image is virtual and erect.

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Solution A Convex Lens of Focal Length 0.10 M is Used to Form a Magnified Image of an Object of Height 5 Mm Placed at a Distance of 0.08 M from the Lens. Calculate the Position, Nature and Size of the Image. Concept: Refraction of Light - Image Formation by Lenses - Convex Lens.