A concave lens has focal length 15 cm . At what distance should the object from the lens be placed so that it forms an image at 10 cm from the lens? Also find the magnification produced by the lens.

Given: The image distance, v = - 10 cm The focal length, f = - 15 cm From the lens formula, 1 f = 1 v - 1 u ⇒ 1 - 15 = 1 - 10 - 1 u ⇒ 1 u = - 1 30 ⇒ u = - 30 cm The object should be placed at 30 cm from the concave lens. The magnification, m = v u = - 10 - 30 = + 0 . 33 The magnification produced by the lens is + 0 . 33 .

E M B I B E

Science for Tenth Class Part - 1 Physics>Chapter 5 - Refraction of Light>Very Short Answer Type Questions>Q 2

EASY

10th CBSE

IMPORTANT

Earn 100

Copy and complete the diagram below to show what happens to the rays of light when they pass through the concave lens:

Important Questions on Refraction of Light

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10th CBSE

IMPORTANT

Science for Tenth Class Part - 1 Physics>Chapter 5 - Refraction of Light>Very Short Answer Type Questions>Q 3

Which type of lenses are:

Thinner in the middle than at the edges?

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10th CBSE

IMPORTANT

Science for Tenth Class Part - 1 Physics>Chapter 5 - Refraction of Light>Very Short Answer Type Questions>Q 3

Which type of lens is thicker in the middle than at the edges?

(Choose from Convex lens/ Concave lens)

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10th CBSE

IMPORTANT

Science for Tenth Class Part - 1 Physics>Chapter 5 - Refraction of Light>Very Short Answer Type Questions>Q 4

A ray of light is going towards the focus of a concave lens. Draw a ray diagram to show the path of this ray of light after refraction through the lens.

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10th CBSE

IMPORTANT

Science for Tenth Class Part - 1 Physics>Chapter 5 - Refraction of Light>Very Short Answer Type Questions>Q 5

What type of images can a convex lens make?
(choose from following: Real/virtual/ real and virtual)

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10th CBSE

IMPORTANT

Science for Tenth Class Part - 1 Physics>Chapter 5 - Refraction of Light>Very Short Answer Type Questions>Q 5

What type of image is always made by a concave lens?
(Choose from: Virtual, erect and enlarged / Virtual, erect and diminished / Virtual, inverted and diminished/ Real, inverted and diminished)

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10th CBSE

IMPORTANT

Science for Tenth Class Part - 1 Physics>Chapter 5 - Refraction of Light>Very Short Answer Type Questions>Q 6

Take down this figure into your answer book and complete the path of the ray.

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