Find the odd one out and give its explanation. Eye piece, Magnifier, Kaleidoscope, Telescope - Science and Technology 1

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MCQ

Find the odd one out and give its explanation.

Options

  • Eye piece

  • Magnifier

  • Kaleidoscope

  • Telescope

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Solution

Kaleidoscope

Explanation-

Kaleidoscope uses mirrors while other devices make use of lenses.

Concept: Convex Lens
  Is there an error in this question or solution?
Chapter 7: Lenses - Find odd one out.

RELATED QUESTIONS

A student focuses the image of a well-illuminated distant object on a screen using a convex lens. After that, he gradually moves the object towards the lens and each time focuses its image on the screen by adjusting the lens.

(i) In which direction, towards the screen or away from the screen, does he move the lens?

(ii) What happens to the size of the image? Does it decrease or increase?

(iii) What happens to the image on the screen when he moves the object very close to the lens?


Study the given ray diagrams and select the correct statement from the following:

(A) Device X is a concave mirror and device Y is a convex lens, whose focal lengths are 20 cm and 25 cm respectively.
(B) Device X is a convex lens and device Y is a concave mirror, whose focal lengths are 10 cm and 25 cm respectively.
(C) Device X is a concave lens and device Y is a convex mirror, whose focal lengths are 20 cm and 25 cm respectively.
(D) Device X is a convex lens and device Y is a concave mirror, whose focal lengths are 20 cm and 25 cm respectively.

 


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 is refracted when it passes:  

 from air into an optically denser medium.


A 1 cm high object is placed at a distance of 2f from a convex lens. What is the height of the image formed?


Where should an object be placed in front of a convex lens so as to obtain its virtual, erect and magnified image?


An object is placed f and 2f of a convex lens. Which of the following statements correctly describes its image? 

(a) real, larger than the object
(b) erect, smaller than the object
(c) inverted, same size as object
(d) virtual, larger than the object


If the object is moved to a point only 3 cm away from the lens, what is the new position, height and nature of the image? 


An image formed on a screen is three times the size of the object. The object and screen are 80 cm apart when the image is sharply focussed. 

 State which type of lens is used. 


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


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 .


Complete the following sentence:

an object is placed at a distance 5 cm from a convex lens of focal length 10 cm. The image formed is virtual, upright and …………….


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.


The image obtained while finding the focal length of convex lens is ....................


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  

State two main differences between a convex and concave lens.

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 ______________.

State the position of object, position of image, nature of image when: Convex lens is used as an erecting lens in terrestrial telescope.


State the nature and position of the object on the principal axis to obtain a real image of the same size


A concave mirror and convex lens are held in water. What changes, if any, do you expect in their focal length?


Why do we say that the ‘2F’ and ‘F’ points of a convex lens can be regarded as a sort of ‘turning points’ as far as the nature of the image formed by it is concerned?


A candle is placed between f and 2f a convex lens. Draw a ray diagram showing the position of the image.


Draw a ray diagram to illustrate the determination of the focal length of a convex lens using an auxiliary plane mirror.


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.


Write the name.

The lens used in simple microscope.


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.


Which of the following statements is true?


  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.

The above image shows a thin lens with a focal length of 5m.

  1. What is the kind of lens shown in the above figure?
  2. If a real inverted image is to be formed by this lens at a distance of 7m from the optical centre, then show with calculation where should the object be placed.
  3. Draw a neatly labelled diagram of the image formation mentioned in (ii).

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


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