Optics and Light

Flashcards about optics and light.

Photon

Fundamental particle of light

Electromagnetic spectrum

Radio, micro, infrared, visible light, ultraviolet, x-rays, and gamma rays (UV, x-rays, and gamma rays are dangerous)

Visible light spectrum (ROYGBIV)

Red, orange, yellow, green, blue, indigo, violet

Incandescent light bulb

Generates light from heat.

Fluorescent light bulb

Converts UV to visible light by passing electricity through mercury.

Neon lamp

Works by passing electricity through a noble gas, emitting light.

LED

Semiconductor that glows when electricity passes through it.

Advantages of LEDs

Last longer, use less energy, and are non-toxic.

Bioluminescence

Production of light in living organisms.

Laser

Concentrated beam of one particular wavelength of light. Light Amplification by Stimulated Emission of Radiation.

Mirror

Sheet of glass backed by metal.

SALT for plane mirror images

Same size, upright, same distance behind mirror, and virtual.

Concave mirrors

Focus light inward.

Convex mirrors

Reflect light rays outward.

Uses for convex mirrors

Side view car mirrors, security mirrors, and hallway mirrors.

Uses for concave mirrors

Make-up mirrors, headlights, and telescopes.

C

Centre of curvature

F

Focal point (half the distance to C).

V

Vertex, the middle point of the mirror.

When a concave mirror image is virtual

When the object is very close to the mirror, inside F (ie. between F and V).

SALT for convex mirror images

Smaller, upright, behind the mirror, virtual.

Refraction

Light enters a new medium and changes speed, resulting in a change of direction.

Index of Refraction

The ratio of the speed of light in a vacuum to the speed of light in a medium.

Rainbow

Water droplets in the air refract light like a prism, splitting it into different colors due to unique wavelengths.

Partial Reflection and Refraction

When there is both reflection and refraction at the same time; some light passes through and some bounces back.

Conditions for total internal reflection

1) Light must be speeding up, and 2) Light must be coming in at an angle greater than the critical angle.

Total internal reflection in diamonds and fiber optic cables

Light comes in and cannot escape, bouncing around inside the diamond.Fibre optic cables also work through total internal reflection, passing a light signal because it cannot escape the cable.

Air over the desert ground is hot; light from the sky refracts, making it appear to come from the desert ground.

Mirage

Convex lenses

Lenses that converge the light rays.

Concave lenses

Lenses that diverge the light rays.

SALT for diverging lens images

Smaller, upright, same side as object, virtual.

How a camera works

Light enters the lens and refracts, landing on the sensor, which converts the light into a digital image.

How a magnifying glass works

Having the object inside F, which creates a larger, virtual image.

Meniscus

A lens that is thinned out and bent to make it more appealing for eyeglasses

2F

Twice the focal length.

Difference between lens and mirror

Mirrors reflect light and lenses refract light.

Human eye vs. digital camera

Diaphragm (iris), retina (sensor/film), converging lenses.

Hyperopia

Far-sightedness, caused by an eye that is too narrow, corrected by a converging lens.

Myopia

Near-sightedness, caused by an eye that is too wide, corrected by a diverging lens.

Laser eye surgery

Lasers are used to reshape the cornea so that it refracts light properly onto the retina.