Curved Mirrors: Locating Images in Concave & Convex Mirrors

Concave & Convex

Curved Mirrors: Terms You Should Know 1.Centre of Curvature, C If you draw a series of lines at right angles to a curved mirror, they will meet at 1 point – this is the centre of curvature. 2. Principal Axis This is a line that goes through the centre of the mirror and is used to help us draw images. 3. Vertex, V The point where the principal axis and the mirror meet.

Curved Mirrors: Terms You Should Know 4. Focal Point, F In a curved mirror, an incident ray that is near and parallel to the principal axis when reflected, will cross the principal axis at a point called the focal point, or F 5. Focal Length The distance between F and V Note: C is always 2x farther from the mirror as F

Curved Mirrors: Label this diagram! VertexPrincipal Axis Focal Point Centre of Curvature Focal Length

Drawing Ray Diagrams to Locate Images in Concave Mirrors Steps Draw the object, so the bottom of it is on the principal axis.  The image will also be on the principal axis, which means we only need to find the top of the image! We only need to draw 2 incident rays, without measuring angles

Concave Mirror Ray Diagrams Ray 1 Draw an incident ray near and parallel to the principal axis  The reflected ray will go through F Ray 2 Draw an incident ray through F  This will reflect parallel to the principal axis Ray 3 An additional ray can be drawn through C  This ray will reflect back on itself

Finding the Image Just like in plane mirrors, to find the image in a curved mirror we simply trace the reflected rays back until they meet. The point where they meet will be the top of the image! We can describe images in concave mirrors using the SALT method.  The characteristics of an image in a concave mirror will depend on the location of the object.

Let’s Try it! Image Attributes: S = Smaller A = Inverted L = Between C & F T = Real

Convex Mirrors When you shine rays of light parallel to the principal axis, the reflected rays travel out and away from each other (they diverge).  Convex mirrors = divergent mirrors  Because of this, the focal point (F) is convex mirrors is behind the mirror.  We still use C, V & the principal axis to help us find images in Convex Mirrors

Concave vs. Convex Mirrors

Drawing Ray Diagrams to Locate Images in Convex Mirrors Steps Use the same three incident rays you used in concave mirrors to find the image in convex mirrors. Characteristics of the Image We use the SALT method to describe images in convex mirrors  There is only one image in convex mirrors

Let’s try it! Image Attributes: S = Smaller A = Inverted L = Between C & F T = Virtual