The Human Eye and the Colourful World
Frequently Asked Questions
The human eye enables us to see objects by detecting and focusing light on the retina.
It is the minimum distance at which a normal eye can see objects clearly, about 25 cm.
The pupil is the eye opening that controls the amount of light entering the eye.
The iris is the colored part of the eye that regulates the size of the pupil.
It is the eye's ability to focus on distant and near objects by adjusting lens shape.
Stars twinkle due to atmospheric refraction of their light by Earth's unsteady atmosphere.
Myopia is near-sightedness, hypermetropia is far-sightedness—both are vision defects.
Myopia is corrected using concave lenses.
Hypermetropia is corrected using convex lenses.
Presbyopia is age-related loss of eye's ability to focus on nearby objects.
It is the bending of light as it passes through different layers of Earth's atmosphere.
Both occur due to atmospheric refraction bending sunlight.
Dispersion is the splitting of white light into its component colors by a prism.
A rainbow forms from sunlight dispersion, refraction, and internal reflection by raindrops.
It is the time for which an image stays on the retina after exposure ends (about 1/16th second).
Red has the longest wavelength and is least scattered, making it visible from a distance.
Rods detect light intensity (black and white), cones detect color.
Color blindness is the inability to distinguish certain colors, often due to lack of cone cells.
The retina is the light-sensitive surface where images are formed for transmission to the brain.
Due to interference of light reflected from the surfaces of the thin film.
It is about 25 cm for a normal-sighted child.
They compensate for focusing defects in the eye, enabling clear vision.
Tyndall effect is the scattering of light by colloidal particles, making beams visible.
Due to the scattering of shorter (blue) wavelengths by Earth’s atmosphere.
The order is: Red, Orange, Yellow, Green, Blue, Indigo, Violet (VIBGYOR).
