Light for Sight

1. What is the approximate least distance of distinct vision for an adult person?

• A) 5 centimeters
• B) 15 centimeters
• C) 25 centimeters
• D) 50 centimeters

2. What is a potential cause for hypermetropia (farsightedness)?

• A) The radius of the eyeball increases.
• B) The converging power of the eye lens increases.
• C) The focal length of the eye lens decreases.
• D) The focal length of the eye lens increases.

3. What is the phenomenon called when a light ray changes its direction at the surface of separation between two transparent media?

• A) Reflection of light
• B) Refraction of light
• C) Dispersion of light
• D) Diffraction of light

4. Which type of lens has a thicker middle part compared to its edges?

• A) Concave lens
• B) Convex lens
• C) Plain lens
• D) Bifocal lens

5. If a lens has a power of +1 D, what does it signify?

• A) It is a concave lens with a focal length of 1 meter.
• B) It is a convex lens that converges a parallel beam at a distance of 1 meter.
• C) It is a convex lens that diverges a parallel beam from a distance of 1 meter.
• D) It is a concave lens that converges a parallel beam at a distance of 1 meter.

6. Why are convex mirrors used for side and rear-view mirrors in cars?

• A) They show a magnified image of the objects.
• B) They form an inverted image.
• C) They cover a large area, making objects look smaller.
• D) They are cheaper to manufacture than plain mirrors.

7. What type of eye defect is characterized by the ability to see nearby objects clearly but not distant ones?

• A) Hypermetropia
• B) Presbyopia
• C) Astigmatism
• D) Myopia