Mirrors are optical devices that work on the reflection principle of light.
Types of Mirror
- Plane Mirror
- Spherical Mirror
Image Formed by Plane Mirror
An object is placed as far ahead as a plane mirror, its image is formed at exactly the same distance behind the mirror. Image size is equal and virtual to the object.
If an object is placed between two plane mirrors inclined at an angle, then many images of the object are formed. The number of images depends on the angle between the two mirrors.
To see the whole image of a person in a plane mirror, the length of the plane mirror should be at least half the size of the person.
When a person comes in front of a flat mirror at a speed, he sees his image coming at double speed.
If a hollow sphere of glass is cut and if one of its surfaces is coated with mercury or red oxide and the other floor acts as a reflector, it becomes a spherical mirror.
Types of Spherical mirror:
(1) Concave Mirror.
(2) Convex Mirror.
When the depth of a spherical mirror is applied to the depth part, it is called a convex mirror.
When an embossed part of a spherical mirror is covered, it is called a concave mirror.
Definition of Spherical mirror?
Center of Curvature, Radius of Curvature, Pole, Pole, Focus, FocusLength, and Principal Axis.
What is the Center of Curvature?
The center of the hollow sphere of which a spherical mirror is a part of is called the center of curvature of the spherical mirror.
What is the Radius of Curvature?
The distance between a point on the spherical mirror and the center of curvature is called the radius of curvature of the spherical mirror.
What is the Pole?
The midpoint of the reflective plane of a spherical mirror is called a pole.
What is Focus?
The point of light coming parallel to the main axis after reflection from the mirror or at which point it appears to come from, the point is called the focus of the spherical mirror.
What is Focal Length?
The distance between the pole and the focus of a spherical mirror is called the focus distance. This distance is half the curvature radius.
What is the Principal Axis?
The line passing through the pole and the center of curvature of a spherical mirror is called the principal axis of the mirror.
The position and nature of the image formed on a concave mirror
Image position of the object Image size of image compared to the object.
Nature of Image
Focus on infinity is very small (just like the point) upside down and real
- On the center of curvature, the inverse, and real shape of the same shape as the object at the center of curvature
- The center of curvature between the center of focus and the center of curvature and the inverse is larger than the center object and the real
- Between the center of curvature and the center of focus and the center of curvature smaller than the object, real and vice versa.
- Behind the mirror between the focus and the pole, a larger and more virtual object than the object behind
- Focus is infinitely larger than the object and infinite
Uses of Concave Mirror
- Used by the doctor to test the eyes, nose, ears, throat, and teeth.
- Used in solar cookers.
- Used in car headlight and searchlight.
- Used by the barber in shaving.
Image formed by Convex Mirror
The image of an object formed in a convex mirror is smaller and smaller than the object between the pole and focus behind the mirror.
Uses of Convex Mirror
- To have a rearview near the driver’s seat in the car.
- In a sodium reflector lamp.