Concave+Mirrors

C- the centre of curvature=radius of a circle F- focal point: the point where light rays converge= half of the centre of curvature Principle Axis- perpendicular from the mirror

To determine the reflection of an image two rays can be drawn: Ray 1) Parallel to the Principle Axis, and then diagonally through the focal point Ray 2) Diagonally to the mirror, and then parallel to the principle Axis (opposite)

Magnification-Same size, enlarged, diminished Attitude-Erect or inverted Position-displacement from mirror surface (ex. Between C and F) Type-real (in front of mirror) or Virtual (behind mirror) The Mirror Equation: 1⁄ƒ= 1⁄di + 1⁄do Where: ƒ= focal length di= distance of image from mirror do= distance of object from mirror

Example 1: Using diagram to the right Determine the distance of the image from the mirror ƒ= 3.00cm do=7.00cm 1⁄di = 1⁄ƒ − 1⁄do 1⁄di = 1⁄3.00cm − 1⁄7.00cm 1⁄di = 0.1905 di = 5.25cm

The Magnification Equation m = hi⁄ho = −di⁄do Where: hi= height of image ho= height of object

Example 2: Using information from previous example Determine the height of the image hi⁄ho = -di⁄do hi⁄1.50cm = −5.25cm⁄7.00cm hi = 1.13cm

Example 3) How to draw a ray diagram