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Define least distance of distinct vision.
What are bifocal lenses?
The diagram below shows the structure of the eye. Choose words from the list below to label the parts A, B, C and D (ciliary muscles, pupil, retina, cornea, iris, optic nerve).
(i) A ray of white light breaks up into its components while passing through a glass prism. Draw a ray diagram to show the path of rays.
(ii) Mark the least deviated color in your diagram.
When a beam of white light is passed through a prism, it splits to form lights of seven colours. Is it possible to recombine the lights of seven colours to obtain the white light again? Explain your answer.
A child sitting in a classroom is not able to read clearly the writing on the blackboard.
(a) Name type of defect from which his eye is suffering.
(b) With the help of a ray diagram show how this defect can be remedied.
What do you mean by the term accommodation? Explain how the eye can see objects at far and near distances.
The near point of a person suffering from hypermetropia is at 50 cm from his eye. What is the nature and power of the lens needed to correct this defect? (Assume that the near point of the normal eye is 25 cm.)
What is the cause for (i) Myopia and (ii) Hypermetropia? Shaw the defective eye and explain how it is corrected?
Draw a labeled diagram of human eye and explain the image formation.
A human eye can focus objects at different distances by adjusting the focal length of the eye lens. This is due to:
Cinematography makes use of:
The human eye forms the image of an object at its:
The change in focal length of an eye lens to focus the image of objects at varying distances is done by the action of the:
The colour of light which is deviated the least by a prism in the spectrum of white light:
Which of the following is correct?
In case of human eye, when light rays enter the eye, most of the refraction occurs at the:
Reddish appearance of the sun at sunrise or sunset is significantly due to:
Identify the correct statement regarding the propagation of light of different colours of white light in air.
Identify the phenomena of light involved in the formation of a rainbow.
The focal length of the eye lens increases when eye muscles:
At noon the sun appears white as:
A prism ABC, with base BC, is placed in four different orientations as shown. A narrow beam of white light is incident on the prism as shown. In which of the following cases, after dispersion, the third colour from the top corresponds to the colour of the sky?
A person cannot see distinctly objects kept beyond 2m. This defect can be corrected by using a lens of power:
Write true or false for the following statements:
Accommodation means the adjustment of light going into the eye for image formation.
A near sighted person can see only nearer objects.
Presbyopia is a type of far sightedness.
Convex lens can be used to correct long-sightedness.
To correct astigmatism we use cylindrical lens.
Short-sightedness is caused due to elongation of the eyeball.
Abnormalities in the normal vision of the eye are called defects of vision.
For a person suffering from myopia, the image of the object is formed in format of the retina.
Light coming from the sun is white light and contains seven colors.
When a beam of white light is passed through the prism, violet color bends the most and red color the least.
Every color travels with the same speed in a transparent medium.
Dispersion of white light occurs because every color travels with a different speed in a transparent medium.