Science study notes
Key Terms

Refraction- the bending or change in the direction of light earn it travels from one medium to another.

Angle of refraction- the angle between the refracted ray and the normal

Index of refraction- the ratio of the speed of light in a vacuum to the speed of light in a medium

Critical angle- the angle of incidence that results in an angle of refraction of 90 degrees

Total internal refraction- the situation when the angle of incidence is greater than the critical angle

Retro-reflector- an optical device in which the emergent ray is parallel to incident ray

Dispersion- the separation of white light into its constituent colours

Converging lens- a lens that is thickest in the middle and that causes incident parallel light rays to converge through a single point after refraction.

Diverging lens- a lens that is thinnest in the middle and that causes light rays to spread apart after refraction

optical centre- point of the exact centre of the lens.

principal focus- the point on the principal axis of a lens where light rays parallel to the principal axis converge after refraction

mirage- virtual image that forms as a result of refraction and total internal reflection in the earth's surface.

emergent ray- the light ray that leaves a lens after refraction

this lens equation- the mathematical relationship among do dI and f
1/do + 1/di = 1/f

accommodation - the changing of a shape of the eye lens by eye muscles to allow a sharply focused image to form on the retina

hyperopia- the inability to see near objects FAR sightedness

positive meniscus- a modified form of the converging lens shape

presbyopia- a form of far sightedness caused by loss of accommodation as a person ages

myopia- the inability to see far object NEAR sightedness

contact lens- a lens that is placed directly on the cornea of the eye

Key Concepts

CH 12 • light changes direction as it passes through a different media • light bends toward the normal when it goes from slow to fast (FST fun science teachers) and (SFA super fun ants) • total internal reflection may occur when an incident ray is aimed at a medium with a lower index of refraction (slow to fast) • many optical devices make use of the refraction and reflection of light. • the refraction and reflection of light can be used to explain natural phenomena • light relates to many careers

refraction can also be accompanied by reflection. for example a pond where u can see the fishes but u can also see the trees. another example is two way mirrors. the higher the index of refraction the slower light travels

GRASS, given required analysis solution and statement n= c/v { n is index of refraction c is the speed of light in a vacuum and v is the speed of light in a media you can also calculate it but using sin i / sin r

angle of refraction is always larger when SFA

total internal reflection occurs when an angle do incidence is larger than the critical angle

fibre optics is light traveling through a glass cable to transfer information. this occurs with a small critical angle total internal reflection occurs. this can be used for computers and cell phone medical usage etc.

triangular primes can be use din binoculars to bend light. this also is used through total internal reflection.

retro reflector return any incident light back in exactly the same direction from which it came. they are also used for bikes and signs on the roads

apparent depth is when an object looks closer ha it actually is. ex fish and paddles in water

the sun seems flat sometimes because it goes from less dense air to more dens. therefore it is refracted.

a mirage can appear when t is traveling from cool air to warm air. index of refraction decreases as air get warmer.the light then creates total internal reflection and since we see light as straight we eel it on the road

shimmering of the moon also happens with