The Human Eye and the Colorful World

What system in the human eye is responsible for focusing light to form an image?

The lens system.

What structure of the eye allows light to enter?

The cornea.

What are the special cells in the retina that convert light into electrical signals called?

Photoreceptors.

What ability does the human eye have to focus on objects at different distances?

Accommodation.

What controls the size of the pupil in the human eye?

The iris.

What happens to the lens when looking at something far away?

The ciliary muscles relax and the lens becomes thinner.

What is the term for the closest distance at which an object can be seen clearly?

Near point.

What is a cataract in relation to the human eye?

A condition where the lens becomes cloudy, causing blurry vision.

What is myopia and how is it corrected?

Near-sightedness where nearby objects are seen clearly, corrected with concave lenses.

What causes presbyopia?

The gradual loss of lens flexibility due to aging.

What is refraction?

The bending of light as it travels through different mediums.

What does the acronym VIBGYOR represent?

Violet, Indigo, Blue, Green, Yellow, Orange, and Red - the colors of the spectrum.

Why do stars appear to twinkle?

Because their light passes through various layers of the atmosphere, causing bending.

What phenomenon explains why the sky appears blue?

Rayleigh scattering.

What is the Tyndall effect?

The scattering of light by small particles in the air.

What is the angle of deviation in relation to prisms?

The angle between the incident ray and the emergent ray.

What is the far point in relation to normal vision?

The farthest distance at which an object can be seen clearly, typically at infinity for a normal eye.

What type of lens is used to correct hypermetropia?

Convex lenses.

What effect does atmospheric refraction have on the appearance of the sunrise and sunset?

It causes the Sun to appear about 2 minutes earlier at sunrise and 2 minutes later at sunset.

How does a prism cause dispersion of white light?

By bending different colors of light at slightly different angles.

What is the effect of ciliary muscles on the lens when focusing on near objects?

The ciliary muscles contract and the lens becomes thicker.