After Refraction Through a Concave Lens Emerges Parallel to the Principal Axis.Draw Ray Diagram to Show Incident Ray and Its Corresponding Emergent Ray. the Principal Axis at a Point. Name the Point. - Physics


A ray of light, after refraction through a concave lens emerges parallel to the principal axis. (a) draw a ray diagram to show the incident ray and its corresponding emergent ray. (b) The incident ray when produces meets the principal axis at a point. Name the point.



(b) The point where incident ray when produced meets the principal axis is called first focus.


Concept: Concave Lens
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Chapter 5: Refraction through a Lens - Exercise 5 (A) 1 [Page 109]


Selina Concise Physics Class 10 ICSE
Chapter 5 Refraction through a Lens
Exercise 5 (A) 1 | Q 17 | Page 109


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

An object is placed 10 cm from a lens of focal length 5 cm. Draw the ray diagrams to show the formation of image if the lens is  diverging.

A beam of light is incident through the holes on one side of a box and emerges out through the holes on its opposite side as shown in the following figure:

The box contains:
(a) a glass prism
(b) a concave lens
(c) a convex lens
(d) a parallel-sided glass slab

When an object is placed 10 cm in front of lens A, the image is real, inverted, magnified and formed at a great distance. When the same object is placed 10 cm in front of lens B, the image formed is real, inverted and same size as the object. 

What is the focal length of lens B?

An object is placed at a distance of 4 cm from a concave lens of focal length 12 cm. Fine the position and nature of the image. 

The power of a converging lens is 4.5 D and that of a diverging lens is 3 D. The power of this combination of lenses placed close together is :
(a) +1.5D
(b) +7.5D
(c) −7.5D
(d) −1.5D

What type of lens is used to correct 


State whether the following statement is true or false:
Short-sightedness can be cured by using a concave lens. 

A person cannot see distant objects clearly. His vision can be corrected by using the spectacles containing:
(a) concave lenses
(b) plane lenses
(c) contact lenses
(d) convex lenses

State two differences between a convex and a concave lens in their (a) appearence, and (b) action on the incident light. 

Show by a diagram, the refraction of two light rays incident parallel to the principal axis on a concave lens by treating it as a combination of a glass block and two triangular glass prisms.

An object is placed on the axis of a lens. An image is formed by refraction in the lens. For all positions of the object on the axis of the lens, the positions of the image are always always between the lens and the object.State three characteristics of the image.

Where will the image be formed if an object is kept in front of a concave lens at a distance equal to its focal length? Draw a ray diagram to illustrate your answer.

State two applications  a concave lens .

How will you differentiate between a convex and a concave lens by looking at (i) a distant object, (ii) a printed page?

Explain the working of an astronomical telescope using refraction of light.


A student obtained clear image of window grills on the screen. But the teacher told him to get the image of a tree far away, instead of window. To get a clear image,  the lens must be ............................

An object is placed at a distance 24 cm in front of a convex lens of focal length 8 cm.

(i) What is the nature of the image so formed ?
(ii) Calculate the distance of the image from the lens.
(iii) Calculate the magnification of the image.

Write the SI unit of focal length of a concave lens.

A lens always forms an image between the object and the lens. 

name the lens.

Choose the correct alternative and rewrite the following: 

Inside water, an air bubble behaves ....................

When an object is kept within the focus of a concave mirror, an enlarged image is formed behind the mirror. This image is :

Draw images in case of a concave lens when the object is at infinity.

Convex lens : converging : : concave lens : _______

Convex magnifying glass is called divergent magnifying glass and concave magnifying glass is called converging magnifying glass.

Distinguish between Concave lens and Convex Lens.

Distinguish between:

Concave Lens and Convex Lens


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