Chapter 4 - Refraction Flashcards
Define:
Refractive index
Is the ratio of the sine of the angle of incidence to the sine of the angle of refraction when lights travels from a vacuum into that medium.
Sin i/Sin r =n
Define:
Refraction of light
The bending of a ray of light when it goes from one medium to another is called refraction.
Define:
Critical Angle
When light travels from a denser to a rarer medium the angle of incidence whose corresponding angle of refraction is 90* is called the critical angle (C) for two media. n= 1/Sin C
Define:
Total internal reflection
When light going from a denser to a rare medium strikes the second medium with an angle of incidence greater the than the critical angle, it does not enter the second medium. It is all reflected back in the denser medium
State :
Laws of Refraction of Light
- The incident Ray, the normal at the point of incidence and the refracted ray all lie in the same plane.
- The ratio of the sine of the angle of incidence to the sine of the angle of refraction is a constant.
Sin i/Sin r = n
Explain:
Real depth
Apparent depth
How deep something is in water.
How deep we see it as.
Explain:
Optical Fibre
A very thin transparent rod through which light can travel by total internal reflection is called an optical fibre.
List 3 uses of Optical fibres
Telecommunications to transmit telephone signals(less energy loss)(smaller)(less interference).
Optical fibres are used to bring light to and from inaccessible parts of the body, an endoscope.
A dentist’s drill uses optical fibres to carry light to very near the drill bit.
List 4 uses of total internal reflection
Reflective road signs
Mirages
Prism reflectors
Optical fibres
Refractive Index in terms of relative speeds
When light, which is a wave, travels from one medium to another, it’s speed usually changes. n= speed of light in air/speed of light in medium
