Light and Vision: Electromagnetic Radiation, Reflection, Refraction, and Eye Anatomy

What is light?

Light is a form of energy called electromagnetic radiation (EMR), commonly known as visible light.

What are some other forms of electromagnetic radiation besides visible light?

Gamma rays, X-rays, microwaves, radio waves, infrared, and ultraviolet.

How fast does light travel?

About 300,000 kilometers per second.

Does light require a medium to travel?

No, light can travel through a vacuum.

What type of wave does light travel as?

Light travels as a transverse wave.

What is the difference between longitudinal and transverse waves?

Longitudinal waves oscillate parallel to the direction of travel, while transverse waves oscillate at right angles to the direction of travel.

What are luminous objects?

Objects that produce their own light, such as stars.

What are non-luminous objects?

Objects that do not produce their own light, such as the moon.

What is reflection?

Reflection is when light bounces off objects, making them visible.

What is the law of reflection?

The angle of incidence is equal to the angle of reflection.

What happens to light when it hits a surface at 90 degrees?

If the incident ray is at 90° to the surface, the angle of incidence is 0°, and the angle of reflection is also 0°.

What is a virtual image?

A virtual image is an image that appears to be located behind a mirror and cannot be projected onto a screen.

What is a real image?

A real image is formed when light rays actually meet at a point and can be projected onto a screen.

What is the difference between concave and convex mirrors?

Concave mirrors converge light and can produce real images, while convex mirrors diverge light and produce virtual images.

What is a convex lens?

A convex lens bulges outward and converges light to a focal point, creating real images.

What is a concave lens?

A concave lens curves inward and diverges light, creating virtual images.

What is refraction?

Refraction is the bending of light when it passes from one medium to another, changing speed.

What happens to light when it passes from a less dense to a denser medium?

It bends towards the normal and slows down.

What happens to light when it passes from a denser to a less dense medium?

It bends away from the normal and speeds up.

What is the function of the cornea in the eye?

The cornea refracts (bends) light to focus it on the lens.

What does the pupil do?

The pupil allows light to enter the eye and can change size based on brightness.

What is the role of the retina?

The retina contains light-sensitive cells (rods and cones) that detect light.

What is the function of the optic nerve?

The optic nerve transfers the image formed on the retina to the brain via electrical signals.

What is lateral inversion?

Lateral inversion is the reversal of an image in a plane mirror, where the right side appears as the left.

What determines the color of an object?

The color of an object is determined by the colors it reflects.

What is the acronym to remember the rules of refraction?

FAST: Faster - Away, Slower - Towards.

What is the function of the pupil?

Allows light to enter the eye and changes size based on brightness.

Where are light-sensitive cells located in the eye?

In the retina.

What does the optic nerve do?

Transfers images formed on the retina to the brain via electrical signals.

What is the role of the lens in the eye?

Focuses light on the retina.

What is the iris?

A circular muscle that controls the size of the pupil and is the colored part of the eye.

What is the sclera?

The tough, protective layer around the eye, commonly referred to as the white part.

What happens to the image formed on the retina?

It is upside down, but the brain interprets and corrects it.

What is accommodation in the context of vision?

The mechanism by which the eye changes its refractive power by altering the lens.

What is myopia?

Also known as short-sightedness, where distant objects are blurry while close objects are clear.

How is myopia corrected?

Using concave lenses.

What is hyperopia?

Also known as long-sightedness, where distant objects are clear but close objects are blurry.

How is hyperopia corrected?

Using convex lenses.

What are contact lenses?

Soft or rigid plastic lenses that sit directly on the eyeball to redirect light onto the retina.

What is the purpose of glasses?

To change the direction of light rays so they are focused directly onto the retina.

What are bi-focal glasses designed for?

To allow clear vision for both close-up and distance objects, with different lens sections for each.

What does laser eye surgery do?

Reshapes the cornea to alter how light is focused, potentially achieving up to perfect 20/20 vision.

What are optical illusions?

Visuals that create deceptive perceptions due to factors like color, pattern, and light.

Why do different people perceive optical illusions differently?

Because everyone's brain processes images in unique ways.

What is total internal reflection?

The complete reflection of light back into a medium when it hits the boundary at a steep angle.