Presentation on theme: "Curved Mirrors Curved mirrors are like plane mirrors"— Presentation transcript:
1 Curved Mirrors Curved mirrors are like plane mirrors they too have smooth, shiny surfaces that reflect light.The surface can either curve in (concave) or out (convex) as shown below
2 Concave mirrors They curve inwards They can form two types of image If the light rays come from something close, the image is upright and magnifiedIt is a virtual image
3 If the light rays come from something distant, they come to a focus after reflection Converging mirrorThey converge (come together) to form a small inverted image which can be picked up on a screenThe type of image is called a real imageThe rays of light actually meet to form it.
4 Rays from very distant things are nearly parallel to each other a concave mirror brings parallel rays to a focus at a point called the principal focus (F)the distance from the mirror to the principal focus is called the focal lengthhighly curved mirror have short focal lengths
5 Remember, the concave mirror is part of a sphere The centre of curvature of a mirror is the centre of the sphere part of whose surface forms the curved mirrorIt is labelled C
6 VThe principal axis of the mirror is the line going through the centre of curvature and the centre of the mirror
7 The point on the mirror's surface where the principal axis meets the mirror is known as the vertex and is denoted by the letter V in the diagram .The distance from the vertex to the center of curvature is known as the radius of curvature (represented by R).The radius of curvature is the radius of the sphere from which the mirror was cut.Since the focal point is the midpoint of the line segment adjoining the vertex and the center of curvature, the focal length would be one-half the radius of curvature.
8 How to locate the image in Converging (Concave) Mirror To determine the image of an object in front of a concave mirror,you need to draw at least two incident rays from the top of the objectthese rays will be reflected off the mirror and may not cross to form an image
11 Drawing an image on Concave mirror Using three kinds of raysThe ray parallel to principle axis is reflected through the focal point (F)2. The ray passing through F is reflected parallel to the principle axis3. The ray passing through the center of curvature C is reflected along its same path through C
13 Forming an image (Object beyond C) Principal axisC F VInverted, virtual, smaller
14 Object between C and FPrincipal axisC F VInverted, real, larger
15 Object inside F or between F and V Principal axisC F VUpright, virtual, bigger
16 Object at CPrincipal axisC F Vinverted, real,same size
17 Convex Mirror Characteristic of convex mirror A convex mirror is part of the outer surface of a hollow sphereA convex mirror produces diverged raysA convex mirror does not form real imagesConvex mirror in daily life, used in cars, and used in stores to observe shoppers.
21 Forming an image in a convex mirror Principal axis
22 Forming an image in convex mirror Three kinds of raysThe ray parallel to the principal axis is reflected as if it is from focal point (f)The ray to focal point is reflected parallel to the principal axisThe ray to the center of curvature C is reflected along its same path through C