EASY
10th CBSE
IMPORTANT
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Write the function of the following part of human eye:

Crystalline lens 

Important Questions on The Human Eye and Colourful World

EASY
10th CBSE
IMPORTANT

Write the function of the following part of human eye:

Ciliary muscles.

MEDIUM
10th CBSE
IMPORTANT

A child is able to read his book comfortably but is unable to read the matter written on the blackboard at a certain distance.

(i) Name the defect of vision he's suffering from.

(ii) With the help of labeled ray diagrams show :

    (a) the above-mentioned defect of vision.

    (b) correction of the above-mentioned defect using a suitable lens.

MEDIUM
10th CBSE
IMPORTANT
Due to the gradual weakening of ciliary muscles and diminishing flexibility of eye lens a certain defect of vision arises. Write the name of this defect. Name the type of lens required by such persons to improve the vision. Explain the structure and function of such a lens. 
MEDIUM
10th CBSE
IMPORTANT
With the help of ciliary muscles, the human eye can change its curvature and thus alter the focal length of its lens. State the changes that occur in the curvature and focal length of the eye lens while viewing (a) a distance object (b) nearby objects. Explain why a normal eye is not able to see distinctly the objects placed closer than 25 cm without putting any strain on the eye.
EASY
10th CBSE
IMPORTANT
Write about the power of accommodation of human eye. Explain why the image distance in the eye does not change when we change the distance of an object from the eye?    
MEDIUM
10th CBSE
IMPORTANT
What is "dispersion of white light"? Draw a labelled diagram to illustrate the recombination of the spectrum of white light. What is it essential that the two prisms used for the purpose should be identical and placed in an inverted position with respect to each other?  
MEDIUM
10th CBSE
IMPORTANT
A person cannot see objects farther than 12 m from the eye clearly. Name the defect of vision he is suffering from and the lens that should be used for the correction of this defect. Illustrate with the help of a diagram how the lens will correct the defective vision.   
MEDIUM
10th CBSE
IMPORTANT

Study the diagram below and answer the following question :

Question Image

 

(i) Name the defect of vision depicted in the diagram.

(ii) List two causes of the said defect.

(iii) Draw a ray diagram for the correction of the above defect using an appropriate lens.