TIR Key Content Flashcards
What happens when light crosses into a less dense medium?
It speeds up, and its wavelength increases.
During refraction, does light bend towards or away from the normal?
Away.
What happens if light alters medium at the critical angle?
The ray will be refracted at 90 degrees, travelling along the medium boundary.
What happens if light hits at an angle surpassing the critical angle?
The ray will not be refracted, and will instead undergo Total Internal Reflection (reflection at an angle equal to that by which a medium is entered).
What are the key conditions necessary for Total Internal Reflection?
The ray must:
- Travel from a more to less dense medium.
- The angle of incidence must exceed the relevant critical angle.
What are optical fibres?
Thin glass cables used for communication.
What do optical fibres rely on?
Total internal reflection.
Why are optical fibres extremely thin?
To accomodate total internal reflection, so that they can bend and still operate.
What can be done to prevent the loss of small quantities of light through refraction in optical fibres?
They can be bundled together,
What are the pros of optical fibres?
Signals aren’t interrupted by atmospheric interference, and communication is considered more secure (harder to tap into).
What are the cons of optical fibres?
They require point to point connection between transmitter and receiver.
What are endoscopes?
Small bundles of optical fibres that form a camera inside of the body, used for medical imaging. Reflected light from organs or tissues is transmitted to doctors, in operations such as by keyhole surgery. These images can be very unclear.
What are CT scans?
The compilation of x-rays to build 3d models. Require the use of ionising waves.
What are P waves?
Primary waves are the first to hit on the advent of an earthquake, and are able to travel through both liquids and solids. These longitudinal waves travel faster than other varieties of seismic waves.
What are S waves?
Transverse waves, second to become evident during an earthquake, and able to travel only through solids.
