Unit 8 Lesson 3 Concave Mirrors concave convex

Unit 8, Lesson 3: Concave Mirrors concave convex

Ray Diagrams for Concave (converging) Mirrors Principle axis (P. A. ) f 1: parallel to P. A. ; bounces through f 2: through f; bounces parallel to P. A. 3: through c; bounces through c c f = focal point c = center of curvature = 2 f

Finding Images Example 1: do = 2. 5 f (object distance) f = 20 cm f Image Characteristics: do = 50 cm Diagram scale 1: 10 c size – smaller location – closer (to the mirror) type – real attitude – inverted

Finding Images Example 2: do = 0. 5 f f = 20 cm do = 10 cm Diagram scale 1: 10 f c Image Characteristics: size – larger location – further type – virtual attitude – upright

Brain Break!

Equations For Image Characteristics d A o ho B f C F c hi D E di M = hi = -di do ho 1 = f 1 + 1 do di G Note: M < 0 inverted M > 0 upright |M| < 1 smaller |M| > 1 larger

Finding Image Characteristics Example: f = 20 cm and do = 2. 5 f = 50 cm 1 = f 1 + 1 do di 1 = 1 + 1 20 di 50 1 = 1 - 1 = 3 di 50 20 100 di = 100 = 33. 3 3 cm M = -di = -33. 3 = - 0. 67 X do 50 f c M < 0 inverted |M| < 1 smaller di = 33 cm in front of mirror di > 0 real

Homework • Pg. 218 Practice Problems #1 -4

Unit 8, Lesson 4: Convex Mirrors Concave convex

Warm-up question If f = 20 cm and do = 0. 5 f, find the characteristics of the image. (Hint: first find di, then M. ) 1 = f 1 + 1 do di 1 = 1 + 1 20 di 10 1 = 1 - 1 = 1 di 10 20 -20 di = -20 cm 1 M = -di = -(-20) = +2 X do 10 f c M > 0 upright |M| > 1 larger di = 20 cm behind mirror di < 0 virtual

Diverging (Convex) Mirrors f Parallel rays diverge from focal point.

Ray rules for a convex mirror Like a concave mirror, but f and c are on the other side: c f

Brain Break!

Example: Find the image characteristics if an object is placed 15 cm from a diverging (convex) mirror of focal length 10 cm. i) ray diagram c f Image Characteristics: ii) calculations size – smaller location – closer type – virtual attitude – upright 1 = 1 + 1 f do di Note: focal length is negative for convex mirrors!! 1 = 1 + 1 1 = 1 di di -10 15 -10 M = -di do = -(-6) 15 = 0. 4 1 1 = di 15 1 -6 di = -6 cm

Homework • Pg. 223 #4, 6, 8, and 10