Question

Q9) An object is placed at 25cm from a convex lens of focal length 20 cm, find the position of the image.​ No spam plz!!​

Answer 1

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Given :-

• An object is placed at 25cm from a convex lens of focal length 20 cm

To Find :-

• Position

Solution :-

We know that

1/f = 1/u + 1/v

1/20 = 1/-25 + 1/v

1/20 - 1/25 = 1/v

5 - 4/100 = 1/v

1/100 = 1/v

100(1) = 1(v)

100 = v

Properties

Formation - Beyond the center of curvature

Type - Real and inverted.

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Answer 2

Here is the correct answer of your question:-

Image will be formed at infinity if object is placed at focus of the lens, i.e., at 20 cm from the lens. Hence,

Shift = 25 – 20 = (1 – 1/µ)t

Shift = 25 – 20 = (1 – 1/µ)tor 5 = (1 – 1/1.5)t

= (5 × 1.5)/0.5 = 15 cm

Hope this helps you ❤️