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# Lakhmir Singh Solutions Class 10 Physics Chapter 4: Reflection of Light

The chapter begins with a discussion on light and its nature. The phenomenon of bouncing back of light rays upon striking an object is called the reflection of light. Silver is considered one of the best reflectors of light. When light reflects from a plane surface such as a mirror, the incident rays, reflected and normal, all lie in the same plane according to the first law of reflection. The second law states that the angle of reflection is always equal to the angle of incidence.

Reflection can be regular or diffuse. The chapter then deals with objects and their images. These images can be virtual or real, depending upon whether the screen is used or not. Next, the formation of an image in a plane mirror when the object is placed at a finite distance is studied. The image formed by a plane mirror has several characteristics, including lateral inversion. Therefore, uses of the plane mirror are also studied as a sub-topic. Next comes the reflection of light from curved surfaces like a concave or convex mirror. The centre of curvature, the radius of curvature, focal length, pole, and principal axis of a spherical mirror are certain topics to be studied.

The derivation is performed to determine the relationship between the radius of curvature and the focal length of a spherical mirror. Students will learn about several rules for obtaining images formed by concave, uses, and the formation of different types of images by the concave mirror when the object is placed at different positions.

• Object between P and F
• Object at F
• Object between F and C
• Object at C
• Object beyond C
• Object at infinity

Similarly, rules for obtaining images formed by a convex mirror, its uses, and formation of image is studied under the following conditions:

• Object is positioned anywhere between P and infinity, and
• Object is placed at infinity

How to find out the focal length of a concave mirror quickly and approximately is studied here. Uses of concave mirrors, sign convention, mirror formula, and linear magnification for spherical mirrors are sub-topics of relevance. Students learn how to differentiate between types of mirrors, i.e. plane mirror, concave mirror, and convex mirror, without getting to touch them.