Advertisements
Advertisements
प्रश्न
Give Reason:
Older people require glasses to read and write.
Advertisements
उत्तर
In old age the flexibility of the lens declines and the lens becomes less convex or opaque leading to weakness of eyesight.
APPEARS IN
संबंधित प्रश्न
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).
To read a book held at a distance of 25 cm, will she need converging or diverging spectacle lenses?
A person is unable to read a book placed closer than 1 meter from his eyes. Identify the defect of vision in his eyes. Draw the ray diagrams to show the defect of vision and its correction.
What eye defect is hypermetropia? Describe with a ray diagram how this defect of vision can be corrected by using an appropriate lens.
Write whether the following is true or false:
A convex lens is used for correcting myopia.
Differentiate between:
Short-sightedness and Long-sightedness.
Nearsightedness : concave lens : : farsightedness : _______
Write scientific reason.
Nearsightedness, this defect can be corrected by using spectacles with concave lens.
What are the causes of ‘Myopia’?
Assertion: Concave mirrors are used as reflectors in torches, vehicle head lights and in search lights.
Reason: When an object is placed beyond the center of curvature of a concave mirror, the image formed is real and inverted.
