Unit 3: Light

 Symbols used: ◦ Ho- height of the object ◦ Hi- height of the image ◦ m-magnification ◦ do (or p)- distance between object and vertex ◦ di (or q)- distance between image and vertex ◦ f- focal length ◦ R- radius of curvature (2F)

 Magnification= m=  Curved mirror and lens equation:

1. Focal length (f)- ◦ Positive for converging mirrors ◦ Negative for diverging mirrors 2. Object distance (do)- is positive 3. Image distance (di)- ◦ Positive for all real images ◦ Negative for all virtual images 4. Heights (Ho and Hi)- ◦ Positive if upright ◦ Negative if inverted 5. Magnification (m)- ◦ Positive image is upright ◦ Negative image is inverted

 Note: sign conventions are needed to get the correct answer when using mirror equations

 Write down what you know and what you need to find  Draw a quick sketch  Find which equation has only one unknown; use this value to solve for other unknowns  Check to make sure answer fits with sketch

 A object 8.0cm high is placed 30cm in front of a converging mirror with a focal length of 20cm. Determine the image location, magnification and image height.  Draw a sketch  Write what you know  Write what you are looking for  Write equation  Substitute numbers in

 An object 12.0cm high is placed 10cm in front of a diverging mirror with a focal length of 4cm. Determine the image location and height.

 Complete practice problem- following slide  When done get answer checked and move on to the- Converging and Diverging mirror equation problems

1. A candle 3.0 cm high is 30.0cm from a converging mirror that has a focal length of 20.0cm. a)Where is the image located? b)What is the height of the image?