Application: Total Internal Reflection

Application:

What are fiber optics?

light inside glass or plastic cable that transmits information

What is the structure of fiber optics cable? How does it use total internal reflection?

glass tube that surrounded by cladding

* glass is denser than cladding
* light enters the cable at angle that is greater than critical angle
* light hits glass it refracts away from normal and in total internal reflection within the glass indefinitely
* in theory light can continue bounding, HOWEVER energy is absorbed and ray becomes weaker and weaker farther it travels

What is mirage and looming?

optical illusions created by difference in air density as a result of temperature

How are image formed in a mirage?

1. air closer to the ground is hotter and air in sky is cooler
2. light rays move away from normal in an arc formation eventually having total internal reflection
3. virtual image is formed
4. as we see in straight line image appears lower than object

How are images formed during looming?

1. air closer to the ground is cooler and air in sky is warmer
2. light rays move away from normal in an arc formation eventually having total internal reflection
3. virtual image is formed
4. as we see in straight line image appear higher than object

What is an Apparent Sunset?

sun appear flattened during sunset

How does Apparent sunset occur regarding total internal reflection?

air closer to earth surface is denser than air up in atmosphere. When sun is below the horizon, air density makes rays bend more. Light from the bottom of the sun has a greater angle of incidence which causes total internal reflection - as this causes it to bend more than ray from top of sun it also appear compressed aka flattened

What is a rainbow?

phenomenon that is caused by dispersion of light under certain atmospheric conditions

How does total internal reflection result in dispersion for a rainbow?

1. during rain light enter raindrops and total internal reflection occurs which results in dispersion
2. partial internal reflection occurs when light hits back of raindrop
3. refracted rays from each colour exit the raindrop
4. we see in straight line so we see rays backwards in red, orange, yellow, green, blue, and violet order

What is a reflector/ retro-reflector? How does it use total internal reflection?

reflective surface found on bike in which the emergent ray is parallel to incident ray

* shape of reflector allow any incident ray that is parallel will bounce at a 90 degree angle twice to reflect light back out of the reflector
* light will bounce bounce at 90 degree once hit another corner inside the reflector and then bounce another 90 degree until it exits the reflector

How does a diamond use total internal reflection?

shape of diamond controls how light will refract which will change how much diamond will sparkle

* deep cut will result in light ray bending out of medium which is less reflection
* shallow cut will result in light to bend out of medium which is less reflection
* ideal cut will allow total internal reflection where rays enter and exit in the same face

What is Apparent Depth?

image appearing deeper or shallower than object as a result of density of medium

How does Apparent Depth use total internal reflection?

when object is in denser medium light refract towards medium

* as we see in a straight line the object appear closer to surface which alters depth of object

What is shimmering and how does it use total internal reflection?

similar to mirage, air in sky in cooler and air closer to water is warmer

* light travels through the cooler/ denser air and moves towards normal
* as it moves downward to warmer total internal reflection occurs and the incidence and reflected ray produce multiple images on waters surface

How do periscopes and binoculars use total internal reflection?

involves triangular prism which does the total internal reflection and reflects almost 100% of light compared to mirrors which absorb some of light. prism need incidence angle greater than 42 degrees for total internal reflection

* in binocular light enter through a lens aka objective lens which transports image upside down
* light passes through 2 prisms which turns the image up right and reflects it towards eyepiece