What Is A Mirror?
In order to understand mirror, one must know what is the phenomenon behind the mirror and what makes it a reflecting material. Mirror is defined as reflecting surface and can be explained by the law of reflection, which states that when a ray of light is made to fall on the reflecting surface, the reflected ray has its angle of reflection, incident ray and the reflected ray are normal to the surface at a point of incidence.
Terms Related To Mirror
- Incident ray: It is defined as a ray of light that hits the surface.
- Reflected ray: It is defined as the ray of light that is reflected back after hitting the surface.
- Normal ray: It is defined as the ray that is 90° to the surface or the ray which is perpendicular to the reflecting surface.
- Refracted ray: It is defined as the incident ray which passes through a second medium resulting in change of direction.
- Angle of incidence: It is defined as the angle between the incident ray the normal at which the incidence occurs.
- Angle of reflection: It is defined as the angle between the reflected ray with respect to the normal at which the reflection occurs.
- Angle of refraction: It is defined as the angle between the refracted ray and the normal at which the refraction occurs.
Types Of Mirrors
Following are the types of mirrors that are most widely used:
- Plane mirror: The images formed from a plane mirror are the reflected images in their normal proportions but reversed from left to right. These are the most widely used mirrors.
- Concave mirrors: These are the spherical mirror that is curved inward and the image obtained from these mirrors depend on the placement of the object. Following is the table explaining the images obtained based on their placement:
Placement of the object Image obtained Placed at infinity Highly diminished, real and inverted Placed beyond the center of curvature Diminished, real and inverted Placed at the center of curvature Same size as that of the object, real and inverted Placed between the center of curvature and principle of focus Enlarged, real and inverted Placed at principle focus Highly enlarged, real and inverted Placed between the principle of focus and the pole Image is obtained behind the mirror, highly enlarged, virtual and erect
- Convex mirror: These are the spherical mirror that is curved outward and the image obtained is virtual, diminished and erect for a real object.
How Does A Mirror Work?
We know that when a light ray falls on the reflecting surface, it gets reflected. We also that light is energy and energy can either be reflected or absorbed. Here, mirrors reflect the light energy. The reason why only mirrors reflective and not the other flat white surface is because the mirror is smooth at a microscopic level. When the light energy hits the rough surface, the light bounces back in all direction and this is known as diffuse reflection. But for a smooth surface, the bouncing back of light happens in one direction and is known as specular reflection.
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