Refraction Flashcards
What is refraction?
The bending of light at a boundary as it passes from one transparent medium to another
How does light refract from a rarer to a denser medium?
Towards the normal
How does light refract from a denser to a rarer medium?
Away from the normal
What is the refracted ray?
The light ray leaving the medium
State the law of refraction.
The incident ray, normal at the point of incidence and refracted ray all lie on the same plane
State Snell’s law.
The ratio of the sine of the angle of incidence to the sine of the angle of refraction is a constant known as the refractive index
To see an image at it’s most accurate depth you would…
…look down at it at 90°
What is the critical angle?
The angle of incidence in the denser medium that results in a 90° angle of refraction
What is total internal refraction?
It occurs when the angle of incidence is greater than the critical angle and light starts to reflect
What are some applications of total internal refraction?
Prisms, fibre optics, mirages, Snell’s window
What are fibre optics?
Light enters the core of a wire at an angle greater than the critical angle so light reflects back and forth in a zig zag pattern
What is an inferior mirage?
Light goes through the dense cold air into the rarer hot air and totally internally reflects off the ground. The image appears below the point of origin, they often appear as puddles
What is a superior mirage?
Light goes through the rare hot air into the denser cold air and totally internally reflects off the ground. The image appears above the point of origin, for example a ship below the horizon may be visible over the surface of the sea.
What is Snell’s window?
When underwater and looking up, you are looking from a dense medium (water) to a rare medium (air). If looking at an angle greater than the critical angle, the light is reflected back, forming a circular window
