Real Image

• Reflection: The bouncing back of rays of light from a polished and shiny surface is called reflection or reflection of light.
• The angle of incidence and angle of reflection is equal.
• The incident ray, reflected ray and normal to the point of reflection lie in the same plane.
• The angle of incidence is denoted by i and angle of reflection is denoted by r .
• The law of reflection is applicable to all types of reflecting surface.
• Mirror: A mirror is a shiny polished object (glass) which reflects most of the rays of light falling upon it.
• One side of mirror is polished with suitable material to make the other side reflective.
• Real Image: An image which is formed in front of the mirror and it can be obtained on a screen is called real image.
• Virtual Image: An image which is formed behind the mirror and cannot be obtained on a screen is called virtual image.
• Plain Mirror: A mirror having a flat surface is called plane mirror.
• A plane mirror always forms virtual and erect image.
• The distance of image and that of object is equal from the mirror.
• The image formed by a plane mirror is laterally inverted.
• Spherical Mirror: Mirrors having curved reflecting surface are called spherical mirrors.
• A spherical mirror is a part of a sphere.
• Concave Mirror: Spherical mirror with reflecting surface curved inwards is called concave mirror.
• Convex Mirror: Spherical mirror with reflecting surface curved outwards is called convex mirror.
• Pole: The centre of reflecting surface of a spherical mirror is known as Pole.
• Pole lies on the surface of spherical mirror.
• Pole is generally represented by ‘P’.
• Centre of Curvature: The centre of sphere, of which the reflecting surface of a spherical mirror is a part, is called the centre of curvature of the spherical mirror.
• Centre of curvature lies in front of concave mirror and lies behind the convex mirror and is not a part of the mirror as it lies outside the mirror.
• Aperture: The diameter of reflecting surface of a spherical mirror is called aperture.
• Principal Axis: Imaginary line passing through the centre of curvature and pole of a spherical mirror is called the Principal Axis.
• Focus or Principal Focus: Point on principal axis at which parallel rays (coming from infinity) converge after reflection is called the Focus or Principal Focus of the spherical mirror.
• Focus is represented by letter F.
• In the case of a concave mirror, parallel rays (coming from infinity) converge after reflection in front of the mirror.
• In the case of a convex mirror, parallel rays (coming from infinity) appear to be diverging from behind the mirror.
• Focal length: The distance from pole to focus is called focal length.
• Focal length is denoted by letter f.
• Focal length is equal to half of the radius of curvature.
• Focal length is represented by the equation f = R 2.
• Plain Mirror Reflecting surface is flat.
• Image is virtual, of same size as mirror, erect and laterally inverted.
• Concave Mirror Reflecting surface is concave.
• Most of the images are real and inverted.
• Virtual image is formed when object is between F and P.