A Pin 2 Cm Long is Placed 12 Cm Away from a Convex Lens a the Principal Axis. If the Focal Length of the Lens is 20 Cm, by Scale Drawing Find the Size of the Image and Its Magnification. - Physics

Advertisements
Advertisements
Numerical

A pin 2 cm long is placed 12 cm away from a convex lens at right angles to the principal axis. If the focal length of the lens is 20 cm, by scale drawing find the size of the image and its magnification.

Advertisements

Solution

Given O = 2 cm, u = 12 cm, f = 20 cm

I = ?,   M = ?

Taking the scale of measurement are : 2 cm = 1 cm on the graph.

In the drawing,

O = 1cm, u = 6cm, f = 10 cm

From the drawing,

I = 2.7 cm

⇒ actual image size I = 2.7 x 2 = 5.4 cm

Magnification m = `"I"/"O" = 5.4/2` = 2.7 cm

Concept: Convex Lens
  Is there an error in this question or solution?
Chapter 2: Light - Exercise 2 [Page 113]

APPEARS IN

Frank ICSE Class 10 Physics Part 2
Chapter 2 Light
Exercise 2 | Q 1 | Page 113

RELATED QUESTIONS

An object of height 2.5 cm is placed at a distance of 15 cm from the optical centre 'O' of a convex lens of focal length 10 cm. Draw a ray diagram to find the position and size of the image formed. Mark optical 'O', principal focus F and height of the image on the diagram.


A student places a candle flame at a distance of about 60 cm from a convex lens of focal length 10 cm and focuses the image of the flame on a screen. After that he gradually moves the flame towards the lens and each time focuses the image on the screen.  

(a) In which direction-toward or away from the lens, does he move the screen to focus the image?
(b) How does the size of the image change?
(c) How does the intensity of the image change as the flame moves towards the lens?
(d) Approximately for what distance between the flame and the lens, the image formed on the screen is inverted and of the same size?


Complete the following table:

Instrument Number of Convex
Lenses
Use
Simple Microscope .............. ..............
Compound Microscope .............. ..............
Telescope .............. ..............

Draw a labelled ray diagram to show how a ray of light passes through a parallel sided glass block: 

 if it hits the glass block at an angle other than 90° (that is, obliquely to the glass block).


For what position of an object a real, diminished image is formed by a convex lens?


What is a lens? 


An object is placed at a distance equal to 2f in front of a convex lens. Draw a labelled ray diagram to show the formation of image. State two characteristics of the image formed.


What is the position of image when an object is placed at a distance of 10 cm from a convex lens of focal length 10 cm?


What kind of lens can form: 

 an erect magnified image? 


Which lens is converging: An equiconcave lens or an equiconvex lens.


Define the term principal foci of a convex lens and illustrate your answer with the aid of proper diagrams.


A beam of light incident on a convex lens parallel to its principal axis converges at a point on the principal axis. Name the point. Draw a ray diagram to show it.


The diagram alongside shows a lens as a combination of a glass block and two prisms.  Name the lens formed by the combination. 


Study the following diagram :

 

What are the points O and O’ called?


The given below figure shows an object OA and its image IB formed by a lens. State three characteristics of the image.


In the following cases, where must an object be placed in front of a convex lens so that the image formed is of same size as the object .


When you focus the image of a distant flag, whose shape is given below, on a screen using a convex lens, the shape of the image as it appears on the screen is

(A)

(B)

(C)

(D)


A student focussed the image of a distant object using a device ‘X’ on a white screen ‘S’ as shown in the figure. If the distance of the screen from the device is 40 cm, select the correct statement about the device.

(A) The device X is a convex lens of focal length 20 cm.

(B) The device X is a concave mirror of focal length 40 cm.

(C) The device X is a convex mirror of radius of curvature 40 cm.

(D) The device X is a convex lens of focal length 40 cm.


Distinguish between:

Concave lens and Convex lens


i. Which type of microscope has the arrangement of lenses shown in the  adjoining figure?
ii. Label the figure correctly.
iii. Write the working of this microscope.
iv. Where does this microscope used?
v. Suggest a way to increase the efficiency of this microscope.


Observe the following figure and answer the questions.

a) Which optical instrument shows arrangement of lenses as shown in the figure?
b) Write in brief the working of this optical instrument.
c) How can we get different magnifications in this optical instrument?
d) Draw the figure again and labelled it properly


Yesh find out F1 and F2 of symmetric convex lens experimentally then which conclusion is true.


Observe the following figure and complete the table:

Points Answer
(i) Position of the object  
(ii) Position of the image  
(iii) Size of the image   
(iv) Nature of the image  

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

state three characteristics of the image.


If an object is placed in front of a convex lens beyond 2F1, then what will be the position, relative size, and nature of an image which is formed? Explain with a ray diagram.


Rewrite the following statement by selecting the correct option:
The power of a convex lens is 2.5 dioptres. Its focal length is ______________.

Which lens can produce a real and inverted image of an object?


Can one bum a piece of paper in daylight by just using a convex lens instead of a match or any direct flame? Support your answer with the help of an appropriate ray diagram.


For a specific glass lens f = 0.5 m. This is the only information given to the student. Which type of lens is given to him and what is its power?


_______ times larger images can be obtained by using a simple microscope.


_______ is a combination of two convex lenses with small focal length.


Object at 2F1 of a convex lens : Image at 2F2 : : Object at F1 : _______


Simple microscope : Number of convex lens one : : compound microscope : _______


: Object near the lens : : ______ :


Find the odd one out and give its explanation.


Find the odd one out and give its explanation.


Write scientific reason.

Adults need bifocal lens spectacle.


Observe the given figure and answer the following questions.

  1. Where is the above type of lens construction used?
  2. What type of image is formed by an objective lens?
  3. What happens instead of placing at Fo if the object is placed in between O and Fo?

Differentiate convex lens and concave lens.


  1. In which type of microscope do you find the lens arrangement as shown in the following diagram?
  2. Write about the working and the use of this microscope.

Distinguish between Concave lens and Convex lens.


Distinguish between:

Concave lens and Convex Lens


Distinguish between Concave lens and Convex Lens.


Distinguish between:

Concave lens and Convex Lens


Distinguish between:

Concave lens and Convex Lens


Share
Notifications



      Forgot password?
Use app×