USES OF PLANE MIRRORS
A mirror is an object with an extremely reflective surface that can clearly reflect an image of any item when placed in front of it. A mirror is also otherwise known as a looking glass because mirrors were primarily used back in the day as a tool for self-grooming. When an object is placed before a mirror, the light that is reflected from the mirror falls on the object, and this creates a reflection on the mirror.
Being a wave reflector, mirrors reflect the incident light waves at an equal and opposite angle while retaining the original degree of curvature and vergence of the incident light waves. The wavelength of the light waves plays a crucial part in the formation of a clear image. The closer the texture of the mirror’s surface is to the wavelength of the light waves, the clearer is the reflection of the original object formed on the mirror. Therefore, any surface that has this property can create a reflection to some degree.
Mirrors can be classified into many types on the basis of their shape, support and reflective materials used, manufacturing methods and their intended application. Based on their shape, mirrors are classified into two types, which is the most chiefly used categorization of mirrors.
- Plane mirrors: Plane mirrors have a smooth and flat reflective surface. Plane mirrors create virtual and upright reflections.
- Spherical mirrors: These types of mirrors have two surfaces; where one is painted with reflective material, and the other side, which is the reflecting side, has a curved shape. Based on the type of curvature, whether the mirror is curved outward or inward, spherical mirrors are further classified into two types as
● Convex mirrors
● Concave mirrors
Unlike spherical mirrors, plane mirrors have a flat reflective surface. When a beam of light falls on the reflective surface of a plane mirror, the angle of its incidence will be equal to the angle of reflection with which it is reflected from the plane mirror. The reflection image created by a plane mirror will always be virtual, upright and of the same shape and dimensions as the original object. The image created on the mirror is the reverse in direction to the original orientation of the object. That is, if a person were to stand in front of a mirror and raise their left hand, the reflection of that person formed on the mirror will raise its “right hand” with respect to that frame of reference. This created reflection is called a perverted image. Plane mirrors are made from materials that are highly reflective, like silver and aluminium. This process of making mirrors is called silvering, after which a thin layer of red lead oxide is spread across the back of the mirror to allow for better reflection.
Uses of Plane Mirrors
- Periscopes: Periscopes are viewing – instruments commonly used in a submarine. For stealth purposes, a submarine cannot come to the surface of the ocean every time it wants to observe the surface. So submarines make use of periscopes, which have a pipe-like body that can reach the ocean's surface by protruding out of the submarine, while it stays underwater. Inside the periscope, a mirror is placed at a specific, calculated angle (usually around 45 0 ). Because of this angle, the incident light falls comfortably on the eyes of the user, allowing them to view the surface in 360 0 if the periscope is also rotated about the same angle.
- Kaleidoscopes: Kaleidoscopes can usually be seen as a toy meant for kids. A kaleidoscope has either a cylindrical body or a prism-like body and contains small, colorful objects like pieces of broken bangles. The inside surface of kaleidoscopes is made of mirrors and so creates reflections really well. When looked inside through a viewing hole, due to the reflections formed, different patterns can be observed as the contents of the kaleidoscope are shaken.
- Torch lights: A torch primarily contains a cylindrical body and a head that contains a bulb and carefully fixed mirrors. When the torch is turned on, the light emitted from the bulb is reflected by the mirrors inside the torch, increasing the intensity of the beam of light that comes out of the torch.
- Headlights: Same as the principle in the case of torch lights, headlights found in vehicles have mirrors on the side of the bulb to help create a brighter beam of
- Dentists: Though concave mirrors are primarily used for this purpose, in some cases, even plane mirrors are used by dentists to look at the patients’ teeth comfortably while working or checking on them.
- Looking mirror: It is probably the most common use of plane mirrors; they have always been and are still being used for personal grooming. At least one mirror can be seen in every household, used for shaving, wearing a tie, putting on makeup and more. They can also be found in salons and clothing stores.