New Blog 4 a New Quarter

The first periodic test is over! That means:
New quarter, project, lessons, assignments, quizzes, tests and a new blog...
What will happen to this quarter?...

The Law of Reflection

The incident, normal, and reflected ray are all in the same plane.
The theta-r (angle of reflection) = theta-i (angle of incidence).

Eye and the Camera

Lens

• bends light rays so that they form a clear image at the back of the eye – on the retina. As the lens is elastic, it can change shape, getting fatter to focus close objects and thinner for distant objects.

Pupil / Aperture

• the entrance of light.

Iris / Diaphragm

• changes the size of the pupil / aperture and allows different amounts of light to enter the eye / camera.

Retina / Film

• produces an image which is sent along the optic nerve for the brain to interpret, rather like developing a camera film.

Choroid / Dark internal Surface

• absorbs excessive light to prevent multiple images formation.

Difference

• their focusing mechanism

-camera changes the distance between the lens and the film.

-the human eye changes the focal length of lens using the ciliary muscles.

Mirror

Two kinds:

1. concave

the image is erect

may produce a real or virtual image

has a positive magnification

object was facing the front of the mirror

2. convex

the image is inverted

always produce virtual image

has a negative magnification

object is place behind the mirror