Find the average or mean value of the focal length of a convex lens from the following observation table when a distant object is used to obtain a sharp image. S. No. Position of the lens a Position of the screen b Focal length of convex lens 1 . 2 cm 17 . 4 cm f 1 = _ _ _ _ _ 2 . 8 cm 23 . 2 cm f 2 = _ _ _ _ _ 3 . 15 cm 30 cm f 3 = _ _ _ _ _

As the object is at infinity, Focal length = distance between lens and image f 1 = 17 . 4 - 2 = 15 . 4 cm f 2 = 23 . 2 - 8 = 15 . 2 cm f 3 = 30 - 15 = 15 cm ∴ Average focal length of the concave mirror, f = f 1 + f 2 + f 3 3 = 15 . 4 + 15 . 2 + 15 3 = 15 . 2 cm

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10th CBSE

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What precautions should be taken for the experiment to determine the focal length of convex lens by obtaining image of a distant object.

Important Questions on Light - Reflection and Refraction

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10th CBSE

IMPORTANT

Science Part-I NEW ERA PHYSICS Textbook for Class X>Chapter 4 - Light - Reflection and Refraction>PRACTICAL SKILLS BASED QUESTIONS>Q 15

The figure shown below, the formation of an image by a convex lens on the white screen. Which distance represent the focal length of the lens?

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10th CBSE

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Science Part-I NEW ERA PHYSICS Textbook for Class X>Chapter 4 - Light - Reflection and Refraction>PRACTICAL SKILLS BASED QUESTIONS>Q 16

In performing the experiment using a convex lens, you find sharp and clear image of a distant object on a screen as shown in the following figure. If you move the screen to the right side then what will you observe about the nature of the image?

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10th CBSE

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Science Part-I NEW ERA PHYSICS Textbook for Class X>Chapter 4 - Light - Reflection and Refraction>PRACTICAL SKILLS BASED QUESTIONS>Q 17

What are the required apparatus to determine the focal length of a convex lens by obtaining an image of a distant object on a screen?

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10th CBSE

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Science Part-I NEW ERA PHYSICS Textbook for Class X>Chapter 4 - Light - Reflection and Refraction>PRACTICAL SKILLS BASED QUESTIONS>Q 18

A student focused the Sun rays using an optical device 'X' on a screen S. What is the device 'X' and what is the focal length of it ?

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10th CBSE

IMPORTANT

Science Part-I NEW ERA PHYSICS Textbook for Class X>Chapter 4 - Light - Reflection and Refraction>PRACTICAL SKILLS BASED QUESTIONS>Q 19

Find the average or mean value of the focal length of a convex lens from the following observation table when a distant object is used to obtain a sharp image.

S. No.	Position of the lens $a$	Position of the screen $b$	Focal length of convex lens
$1 .$	$2 cm$	$17.4 cm$	$f_{1} =_____$
$2 .$	$8 cm$	$23.2 cm$	$f_{2} =_____$
$3 .$	$15 cm$	$30 cm$	$f_{3} =_____$

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10th CBSE

IMPORTANT

Science Part-I NEW ERA PHYSICS Textbook for Class X>Chapter 4 - Light - Reflection and Refraction>PRACTICAL SKILLS BASED QUESTIONS>Q 20

What are the sources of error in performing the experiment to determine the focal length of a convex lens by obtaining an image of a distant object on a screen?

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10th CBSE

IMPORTANT

Science Part-I NEW ERA PHYSICS Textbook for Class X>Chapter 4 - Light - Reflection and Refraction>PRACTICAL SKILLS BASED QUESTIONS>Q 21

What is the correct method of placing the pins

P_{3}

and

P_{4}

in the experiment to trace the path of a ray of light through a rectangular glass slab using pins

P_{1}, P_{2}, P_{3}

and

P_{4}

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10th CBSE

IMPORTANT

Science Part-I NEW ERA PHYSICS Textbook for Class X>Chapter 4 - Light - Reflection and Refraction>PRACTICAL SKILLS BASED QUESTIONS>Q 22

Give the diagram which represents the correct angle of incidence

i

, angle of refraction

r

and angle of emergence

e

for the experiment tracing the path of light passing through a rectangular glass slab.

What precautions should be taken for the experiment to determine the focal length of convex lens by obtaining image of a distant object.

Important Questions on Light - Reflection and Refraction

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