Chapter 9

Plane mirror

- flat sheet of glass has smooth silver coating on one side (coating is there to protect from damage) light strikes the mirror coating reflects light because the coating is smooth giving a regular reflection and clear image. -produces a virtual image that is upright and same size as object, switches left and rights

Real image

- forms when light rays actually meet - if the object is farther away from the mirror than the focal point they form a real image - are upside down can be smaller larger or the same size as the object

Convex mirror

- mirror with a surface that curves outward - reflected rays spread out but appear to come from the focal point ( a focal point in a convex mirror is the point the rays seem to come from) produce virtual images that are always smaller than the object

Convex lens

- thicker in the center than the edges , converging light rays - as light rays parallel to the optical axis pass through a convex lens they are bent towards the center of lens, the rays meet at a focal point - the more curved the lens the more it refracts light - acts like concave mirror because it focuses the image or rays of light the image is larger for a virtual image - when the object is between the focal point and lens a virtual image is created - if the object is outside of the focal point a real image is created a smaller, larger or the image is the same size as the object

Concave lens

- thinner in the center than the edges, diverging lens - light rays parallel to the optical axis through the concave lens, they bend away from the optical axis and never meet - Produce only virtual images because parallel. rays of light passing through the lens never meet - Concave lenses always produce virtual and an upright images which are smaller than the object - an image is located where the light rays appear to come from

Refraction

-It causes you to see something that may not actually be there, as light passes through one medium to the next it is refracted. Refraction is when light rays bend. -When light rays enter a new medium at a angle the change in speed causes the light rays to bend. -Some mediums cause light to bend more then others, when light rays pass from air to water the light slows down causing it to bend

How is a rainbow created?

1.) white light enters a prism, each wavelength is refracted by a different amount, the longer the wavelength the less the wave is bent 2.) The water droplet acts like a prism and refracts the colors the difference in refraction causes white light to spread into the rainbow colors. 3.) The colors reflect based on the wavelength 4.) Finally, the colors separate into 7 colors

Lens

Curved piece of glass or other transparent material that reflects light, it forms an image by refracting light rays that pass through it. The type or image formed by a lens depends on the shape of the lens and the position of the object.

Diffuse reflection

Diffuse reflection- parallel rays of light hit an uneven surface, each ray obeys the law of reflection and hits the surface at a different angle, not clear image/ don't see image, most objects reflect diffusely.

Two ways surfaces can reflect light

Regular reflection and Diffuse reflection

Regular reflection

Regular reflection- parallel rays of light hit a smooth surface, all the light rays reflect at the same angle, see clear image, shiny surfaces produce regular reflections.

Absorption

The more transparent an object is the less light it will absorb, an opaque or not transparent will both reflect and absorb light

What factors affect the speed of a wave?

The speed of a wave through a substance is determined by the substances's is determined by the substance's physical properties. - sound waves also travel at different speeds through different substances - Temperature, as temperature increases the speed of sound in air also increases. For solids, a temperature increase causes wave speeds to decrease - Compressibility (measure of how hard a substance is to compress or squeeze) and density (mass in a given volume) - If either the density or the compressibility of a substance increases the speed of sound through that substance will decrease

What happens when light hits an object

When light hits an object it canbe reflected, refracted and/or absorbed

Index of Refraction

a measure of how much a light ray bends when it enters that medium, the higher the index of refraction the more it bend light, solids bend light more

Mirage

an image of a distant object caused by refraction of light, light travels faster in hot air

Virtual image

an image that forms where light seems to come from, the virtual image is produced behind the mirror it cant be seen or touched - if the object is between the mirror and the focal point the reflected rays produce a virtual image - virtual images produced by concave mirrors are always larger than the object

Optical axis

imaginary line that divides the mirror in half (refer to equator)

Rays

light waves as straight lines that reflect of surfaces , get absorbed and are refracted

Concave mirrors

mirror with a surface that curves inward like the inside of a bowl, reflects parallel rays of light so they the rays meet at a point where they can form images - can produce virtual or real images it depends on the location of the object - produce magnified images you see in a makeup mirror- virtual images produced by concave mirrors are always larger than the object

Focal point

the point at which rays parallel to the optical axis reflect and meet