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View kacleaveland's map Taken in a place with no name (See more photos or videos here) "Have you ever approached a giant concave mirror? See your upside-down image suspended in mid-air. Walk through the image to see a new reflection, right-side-up and greatly magnified. In the background you see reflected a room full of visitors enjoying other Concave Mirrors • Curves inward
Concave Mirrors • AKA converging mirror • Described as a mirror with a surface that curved inward like a bowl
Terminology Vertex Centre of Curvature (C) Principle Axis (PA) Focus (F)
Light Rays in a Concave Mirror Purpose: To determine how light behaves in a concave mirror Observations:
Rules for Concave Mirrors Lab Outline mirror in book, and label Principle axis. Shine light bulb of ray box at mirror. You should notice all the rays focus on 1 point (the focus). Mark and label this point F. Measure the distance from the mirror to point F. Use this distance to mark C, a point on the other side of F. Shine a single light ray through F at mirror. Copy the light beam path. Shine a light ray parallel to the P.A. Copy the light beam path. Shine a light ray through C. Copy the light beam path. Shine a light hitting the vertex. Copy the light beam.
Analysis: What happens when you shine a light ray through the focus (F)? What happens when you shine a light ray parallel to the principle axis (PA)? What happens when you shine a light ray through the centre of curvature (C)? What happens when you shine a light ray at the vertex (V)?
Light Ray Rules for Concave Mirrors • A light ray parallel to P.A. reflects through F. • A light ray that passes through F will reflect parallel to P.A. • A light ray hitting the vertex (perpendicular to P.A.) will follow Өi & Өr reflection rule.
Using Light Ray Rules to Find an Image Case 1: An object outside C Case 2: An object between C and F Case 3: An object on F Case 4: An object between F and Mirror
Concave Mirror Applications • A searchlight/car headlight • radiates light rays from focus to reflect rays parallel (beam of light) • Satellite Dish • TV dish receives parallel rays and reflects them to focus where wave detector is • Cosmetic Mirrors - Large virtual images provide magnified face