Important Points Of Chapter "Human Eye and the Colourful World":
1. The human eye is one of the most valuable sense organs that enables us to see the world around us.
2. The structure of the human eye consists of the cornea, iris, pupil, lens, ciliary muscles, retina, and optic
nerve.
3. The cornea is a transparent bulge on the outer surface of the eye that helps in the refraction of light.
4. The iris is the colored part of the eye that controls the size of the pupil.
5. The pupil is the small aperture that regulates the amount of light entering the eye.
6. The lens is a transparent structure located behind the iris that helps in focusing the light onto the retina.
7. The ciliary muscles control the shape of the lens, allowing it to adjust its focal length.
8. The retina is the innermost layer of the eye that contains light-sensitive cells called rods and cones.
9. Rods are responsible for black and white vision and function in dim light, while cones are responsible for
color vision and work in bright light.
10. The optic nerve carries the electrical signals from the retina to the brain, where visual information is
processed.
11. The accommodation is the ability of the eye to adjust the focal length of the lens to see objects at
different distances.
12. The near point is the minimum distance at which the eye can see objects clearly without strain.
13. The far point is the maximum distance at which the eye can see objects clearly without strain.
14. Defects of vision include myopia (nearsightedness), hypermetropia (farsightedness), and presbyopia
(age-related farsightedness).
15. Myopia is corrected using a concave lens, hypermetropia is corrected using a convex lens, and
presbyopia is corrected using bifocal lenses.
16. The phenomenon of the dispersion of white light into its component colors is called dispersion.
17. When light passes through a prism, it splits into a spectrum of colors known as a rainbow.
18. The colors of the spectrum are red, orange, yellow, green, blue, indigo, and violet (ROYGBIV).
19. The different colors in the spectrum have different wavelengths and frequencies.
20. White light is a combination of all the colors of the spectrum, while black is the absence of light.
21. The colors of objects are determined by the selective reflection, absorption, and transmission of light.
22. The primary colors of light are red, green, and blue (RGB), and the secondary colors are cyan, magenta,
and yellow.
23. When two primary colors are mixed, they produce secondary colors.
24. Complementary colors are pairs of colors that, when combined, produce white light.
25. The phenomenon of persistence of vision is responsible for the illusion of a moving picture in movies
and television.
26. Some animals can see beyond the range of human vision, such as ultraviolet and infrared light.
, Formulas:
1. The formula for the magnification produced by a lens:
Magnification (m) = Height of image (hᵢ) / Height of object (hₒ) = - Image distance
(v) / Object distance (u)
2. The lens formula:
1/v - 1/u = 1/f
Where:
v is the image distance (distance of image from the lens)
u is the object distance (distance of object from the lens)
f is the focal length of the lens
3. The power of a lens formula:
P = 1/f
Where:
P is the power of the lens (measured in diopters, D)
f is the focal length of the lens (measured in meters, m)
4. The formula for the near point (np) of the eye:
np = 25 cm
5. The formula for the far point (fp) of the eye:
fp = Infinity (∞)
6. The formula for the refractive index (n) of a medium:
n=c/v
Where:
n is the refractive index of the medium
c is the speed of light in vacuum (3 × 10^8 m/s)
v is the speed of light in the medium
7. The formula for the angle of deviation (δ) by a prism:
δ=i-e
Where:
δ is the angle of deviation
i is the angle of incidence
e is the angle of emergence
8. The formula for the critical angle (C) for total internal reflection:
C = sin⁻¹(n₂ / n₁)
Where:
C is the critical angle
n₁ is the refractive index of the medium of incidence
n₂ is the refractive index of the medium of refraction
9. The formula for the magnifying power of a simple microscope:
Magnifying Power (M) = 1 + (D / 25)
Where:
M is the magnifying power
D is the least distance of distinct vision (25 cm)
10. The formula for the magnifying power of a compound microscope:
Magnifying Power (M) = Magnification of objective lens × Magnification of
eyepiece
1. The human eye is one of the most valuable sense organs that enables us to see the world around us.
2. The structure of the human eye consists of the cornea, iris, pupil, lens, ciliary muscles, retina, and optic
nerve.
3. The cornea is a transparent bulge on the outer surface of the eye that helps in the refraction of light.
4. The iris is the colored part of the eye that controls the size of the pupil.
5. The pupil is the small aperture that regulates the amount of light entering the eye.
6. The lens is a transparent structure located behind the iris that helps in focusing the light onto the retina.
7. The ciliary muscles control the shape of the lens, allowing it to adjust its focal length.
8. The retina is the innermost layer of the eye that contains light-sensitive cells called rods and cones.
9. Rods are responsible for black and white vision and function in dim light, while cones are responsible for
color vision and work in bright light.
10. The optic nerve carries the electrical signals from the retina to the brain, where visual information is
processed.
11. The accommodation is the ability of the eye to adjust the focal length of the lens to see objects at
different distances.
12. The near point is the minimum distance at which the eye can see objects clearly without strain.
13. The far point is the maximum distance at which the eye can see objects clearly without strain.
14. Defects of vision include myopia (nearsightedness), hypermetropia (farsightedness), and presbyopia
(age-related farsightedness).
15. Myopia is corrected using a concave lens, hypermetropia is corrected using a convex lens, and
presbyopia is corrected using bifocal lenses.
16. The phenomenon of the dispersion of white light into its component colors is called dispersion.
17. When light passes through a prism, it splits into a spectrum of colors known as a rainbow.
18. The colors of the spectrum are red, orange, yellow, green, blue, indigo, and violet (ROYGBIV).
19. The different colors in the spectrum have different wavelengths and frequencies.
20. White light is a combination of all the colors of the spectrum, while black is the absence of light.
21. The colors of objects are determined by the selective reflection, absorption, and transmission of light.
22. The primary colors of light are red, green, and blue (RGB), and the secondary colors are cyan, magenta,
and yellow.
23. When two primary colors are mixed, they produce secondary colors.
24. Complementary colors are pairs of colors that, when combined, produce white light.
25. The phenomenon of persistence of vision is responsible for the illusion of a moving picture in movies
and television.
26. Some animals can see beyond the range of human vision, such as ultraviolet and infrared light.
, Formulas:
1. The formula for the magnification produced by a lens:
Magnification (m) = Height of image (hᵢ) / Height of object (hₒ) = - Image distance
(v) / Object distance (u)
2. The lens formula:
1/v - 1/u = 1/f
Where:
v is the image distance (distance of image from the lens)
u is the object distance (distance of object from the lens)
f is the focal length of the lens
3. The power of a lens formula:
P = 1/f
Where:
P is the power of the lens (measured in diopters, D)
f is the focal length of the lens (measured in meters, m)
4. The formula for the near point (np) of the eye:
np = 25 cm
5. The formula for the far point (fp) of the eye:
fp = Infinity (∞)
6. The formula for the refractive index (n) of a medium:
n=c/v
Where:
n is the refractive index of the medium
c is the speed of light in vacuum (3 × 10^8 m/s)
v is the speed of light in the medium
7. The formula for the angle of deviation (δ) by a prism:
δ=i-e
Where:
δ is the angle of deviation
i is the angle of incidence
e is the angle of emergence
8. The formula for the critical angle (C) for total internal reflection:
C = sin⁻¹(n₂ / n₁)
Where:
C is the critical angle
n₁ is the refractive index of the medium of incidence
n₂ is the refractive index of the medium of refraction
9. The formula for the magnifying power of a simple microscope:
Magnifying Power (M) = 1 + (D / 25)
Where:
M is the magnifying power
D is the least distance of distinct vision (25 cm)
10. The formula for the magnifying power of a compound microscope:
Magnifying Power (M) = Magnification of objective lens × Magnification of
eyepiece
