Theory of Concept

Have you ever wondered how mirrors work?

A mirror is made up of a smooth glass surface and a thin layer of metal film behind it.

When light hits the mirror, it passes through the glass surface and reaches the metal film. However, the metal film doesn't absorb any colours of light.

Hence, mirror reflects all the light directly, which results in seeing our own reflection. (CrashCourse, 2017)

Figure 1.1: Diagram of how a mirror reflects light,From Finn (n.d), HowStuffWorks, Adapted from: https://science.howstuffworks.com/innovation/everyday-innovations/mirror2.htm

There are 3 main types of mirrors, and they all have different properties. They are :

Plane mirror
Concave mirror
Convex mirror

Figure 1.2: Woman looking in the mirror and smiling, n.d. Adapted from: https://www.innoverqc.ca/magasinage/pour-la-nouvelle-annee-perfectionnez-votre-routine-beaute/attachment/woman-looking-in-the-mirror-and-smiling/

Plane Mirror

Plane mirrors have a smooth surface; they reflect light without changing its convergence and divergence. When light rays strike onto the plane mirror, it will reflect back at the same angle.

Properties of Image formed on Plane Mirror:

Virtual
Upright
Lateral Inversion
Same size as the object

Not all mirrors have a flat surface.Some mirrors have a curved surafce and are known as curved mirror.Such as, the convex and concave mirror. (Wonderopolis, n.d.)

Figure 1.3: Image formation in concave and convex mirrors. Adapted from BYJU'S (n.d.), https://byjus.com/physics/concave-convex-mirrors/

Concave mirror

A curved mirror, where it reflects on the inner part of the mirror. They are also known as converging mirrors, as they make light rays converge after reflection. Concave mirrors create both real and virtual images. When it is close to an object, it will form a magnified, upright and virtual image.

However, when the object and the mirror move further away from each other, the image size will decrease. The image changes from a virtual to a real image after reaching a certain distance, forming a real and inverted image on the opposite side of the mirror. (BYJU'S, n.d.)

Figure 1.5: Image of concave mirror image formation summary. Adapted from BYJU'S (n.d.), https://byjus.com/physics/concave-convex-mirrors/

Figure 1.4: Image formation in concave and convex mirrors. Adapted from BYJU'S (n.d.), https://byjus.com/physics/concave-convex-mirrors/

Convex mirror

In contrast to the concave mirror, the convex mirror has a reflecting surface outside the curved shape. They are also known as diverging mirrors, as they cause the light beam to diverge after reflection.

Convex mirrors always form a virtual, erect and reduced image no matter the distance away from the mirror. (BYJU'S, n.d.)

Figure 1.6: Image of convex mirror image formation summary. Adapted from BYJU'S (n.d.), https://byjus.com/physics/concave-convex-mirrors/

Page updated

Google Sites

Report abuse