Write law in a given figure. - Science and Technology 1

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One Line Answer

Write law in a given figure.

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Solution

Rule III: When the incident ray passes through the optical centre of the lens, it passes without changing its direction.

Concept: Lens
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Chapter 7: Lenses - Answer the Following

RELATED QUESTIONS

State the position of the object in front of a converging lens if It produces a real and same size image of the object


Show by a ray diagram that a diverging lens cannot form a real image of an object placed anywhere on its principal axis.


Draw a ray diagram to show how a converging lens is used as a magnifying glass to observe a small object. Mark on your diagram the foci of the lens and the position of the eye.


Draw a figure explaining various terms related to a lens.


Distinguish between:

Farsightedness and Nearsightedness.


State whether the given statement is true or false:
A concave lens is a converging lens.


What do you understand by focal plane of a lens?

Aniket from Std. X uses spectacles. The power of the lenses in his spectacles is - 0.5 dioptre.
Answer the following questions:
  1. State the type of lenses used in his spectacles.
  2. Name the defect of vision Aniket is suffering from.
  3. Find the focal length of the lenses used in his spectacles.

How are the distance of object (u), the distance of image (v), and focal length (f) of a lens-related?


We can burn a piece of paper by focussing the sun rays by using a particular type of lens. Name the type of lens used for the above purpose.


From the nature of the refracted rays, shown in the diagram interpret the nature of the lens represented by the dotted line.


Draw a ray diagram to show the formation of an inverted and diminished image of an object by a lens. Name the lens used. State the position of the object with respect to the lens used. State one more characteristic of the image.


Draw the ray diagrams of a converging lens, when the object is placed at 2F on the principal axis. Write down the nature, position, and size of the image in both cases. Use only two rays in the diagrams.


The given ray diagram illustrates the experimental set up for the determination of the focal length of a converging lens using a plane mirror.

(i) State the magnification of the image formed.
(ii) Write two characteristics of the image formed.
(iii) What is the name given to the distance between the object and optical centre of the lens in the above diagram?


A ray of light gets refracted ______ while entering the lens.


The point inside the lens on the principal axis through which light rays pass without changing their path is called _______.


Write the name.

The distance between focus and optical centre.


Write the name.

The imaginary line passing through two optical centres of lens


When the incident ray is parallel to the principal axis, the refracted ray passes through the principal focus.


The virtual image of object seen by the eye depends on the angle subtended by the object with the eye.


Write an Explanation.

The optical centre of the lens


Write an Explanation.

Principal focus


Write an Explanation.

Focal length


Write scientific reason.

A convex lens is called a converging lens.


Choose the correct option from the bracket and complete the stanza.

(colour blind, actual, conical, light-sensitive, rodlike, colours)

The retina in our eyes is made up of many _______ cells. These cells are shaped like a rod and like a cone. The _______ cells respond to the intensity of light and give information about the brightness or dimness of the object to the brain. The _______ cells respond to the colour and give information about the colour of the object to the brain. Brain processes all the information received and we see the _______ image of the object. Rod like cells respond to the faint light also but ______ cells do not. Some people lack conical cells responding to certain colours. These persons cannot recognize those colours or cannot distinguish between different ______. These persons are said to be ______.


Explain with a ray diagram the position, size, and nature of the various images formed by a convex lens.

Object between F1 and O


The image formed by a lens is always virtual, erect and smaller in size than an object kept at different positions in front of it. Identify the nature of the lens.


State whether the following statement is True or False

A concave lens can be used to produce an enlarged and erect image.


State whether the following statement is True or False

A convex lens always produces a real image.


Observe the figures given in Figure 15.1 carefully.

The given figures show the path of light through lenses of two different types, represented by rectangular boxes A and B. What is the nature of lenses A and B?


Two different types of lenses are placed on a sheet of newspaper. How will you identify them without touching them?


It was observed that when the distance between an object and a lens decreases, the size of the image increases. What is the nature of this lens? If you keep on decreasing the distance between the object and the lens, will you still be able to obtain the image on the screen? Explain.


A convex lens ‘A’ of focal length 20 cm and a concave lens ‘B’ of focal length 5 cm are kept along the same axis with a distance ‘d’ between them. If a parallel beam of light falling on ‘A’ leaves ‘B’ as a parallel beam, then the distance ‘d’ in cm will be ______.


A point object is placed at a distance of 60 cm from a convex lens of a focal length of 30 cm. If a plane mirror were put perpendicular to the principal axis of the lens and at a distance of 40 cm from it, the final image would be formed at a distance of:


A convex lens ‘A’ of focal length 20 cm and a concave lens ‘B’ of focal length 5 cm are kept along the same axis with a distance ‘d’ between them. If a parallel beam of light falling on ‘A’ leaves ‘B’ as a parallel beam, then the distance ‘d’ in cm will be ______


A point object is placed at a distance of 60 cm from a convex lens of focal length 30 cm. If a plane mirror were put perpendicular to the principal axis of the lens and at a distance of 40 cm from it, the final image would be formed at a distance of :


The power of a convex lens of focal length 25 cm is ______.


Draw the ray diagram of convex lens making image when object is at radius of curvature (2F1).

  1. An object is placed vertically at a distance of 20 cm from a convex lens. If the height of object is 5 cm and focal length of the lens is 10 cm, what will be its position, size and nature of image?
  2. Flow much bigger will the image be as compared to the object?

Distinguish between:

Concave Lens and Convex Lens


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