4. Reflection of light
of
curved surfaces
surfaces
A light ray passing through the focal
mirror reflected from
Draw the reflected ray
point of
son
ولم
Answers
Answer:
We have already looked at reflection by plane mirrors in topic 8. When the reflecting surface is instead curved, we call it a curved mirror. There are two types of curved mirrors; concave and convex mirror. Curved mirrors whose reflecting surfaces curve inwards are called concave mirrors while those whose reflecting surfaces bulge outwards are called convex mirrors.
Pole P- it is the centre of the mirror.
Centre of curvature C- it is the centre of the sphere of which the mirror is part.
Radius of curvature r- it is the radius of the sphere of which the mirror is part.
Principal axis- it is a line drawn through the pole of the mirror and the centre of curvature.
Principal focus F – for a concave mirror, it is the point at which all rays parallel and close to the principal axis converge at after reflection. In the case of a convex mirror, it is the point at which all rays parallel and close to the principal axis appear to diverge from after reflection.(See the figure above). It is also called the focal point.
Focal plane- it is a plane perpendicular to the principal axis and passes through the focal point. It is the plane where parallel rays but not parallel to the principal axis converge at or appear to diverge from after reflection.
Focal length f- it is the distance between the pole of the mirror and its focal point.
When rays are produced behind the mirror, they are indicated using dotted lines. This means that they are imaginary or virtual. Hence the focal point and focal length of a concave mirror are real while the focal point and focal length of a convex mirror arevirtual. A real focal length is given a positive sign while a negative focal length is given a negative sign.
Explanation:
it's all about in and out... double meaning