Activity 13.3

13.2.3 Activity 13.3

Description

Quick Overview

This section explains the formation of virtual images using a plane mirror and the laws of reflection.

Standard

In this section, students conduct activities that demonstrate how images are formed by plane mirrors, focusing on concepts such as the laws of reflection, the behavior of light when it strikes a reflecting surface, and the resulting virtual images that appear as though they are behind the mirror.

Detailed

Activity 13.3: Formation of Images by a Plane Mirror

In this activity, a light source is positioned in front of a plane mirror to observe how light rays reflect off the mirror. Two rays, OA and OC, are incident on the mirror at points A and C, respectively. By drawing normals at these points and using the laws of reflection, students can discover the direction of the reflected rays AB and CD. Interestingly, although the reflected rays appear to converge at a point I behind the mirror, they do not actually meet; instead, this point is referred to as a virtual image. This understanding provides insight into how mirrors create images that undergo lateral inversion.

The section emphasizes several laws of reflection: (1) the angle of incidence is always equal to the angle of reflection, and (2) the incident ray, the reflected ray, and the normal line all lie in the same plane. Furthermore, the exploration of multiple images formed by varied angles between two plane mirrors, as well as the design and use of devices like periscopes and kaleidoscopes, illustrates the broader applications of these reflection principles.

Key Concepts

  • Law of Reflection: The angle of incidence equals the angle of reflection.

  • Virtual Images: Formed behind the mirror and do not actually meet real light rays.

  • Lateral Inversion: The left and right sides of an image are swapped.

  • Plane Mirror: A flat mirror that creates a clear reflection of images.

Memory Aids

🎡 Rhymes Time

  • In front of the glass, don’t you see, Left becomes right, that's the key!

πŸ“– Fascinating Stories

  • Once there was a boy named Sam who looked into a mirror. Each time he waved, the mirror waved back but switched his hands. This mystery made Sam giggle and taught him how mirrors work!

🧠 Other Memory Gems

  • I-R-N: Incident Ray, Reflected Ray, Normal.

🎯 Super Acronyms

V-I-L

  • Virtual Images are Laterally inverted.

Examples

  • When looking into a mirror, your right side appears on the left side of your reflection, exemplifying lateral inversion.

  • A periscope uses two mirrors at an angle to enable viewers to see over obstacles.

Glossary of Terms

  • Term: Angle of Incidence

    Definition:

    The angle formed between the incident ray and the normal at the point of incidence.

  • Term: Angle of Reflection

    Definition:

    The angle formed between the reflected ray and the normal at the point of incidence.

  • Term: Virtual Image

    Definition:

    An image formed by diverging rays that appear to be coming from a location behind the mirror.

  • Term: Lateral Inversion

    Definition:

    The phenomenon where left and right are switched in an image formed by a mirror.

  • Term: Plane Mirror

    Definition:

    A flat, smooth surface that reflects light to form images.