Reflection of Light
Whenever light bounces off an item, it is called reflection. The light will reflect at the same angle as it hit the surface if the surface is smooth and glossy, such as glass, water, or polished metal. Specular reflection is the term for this. A smooth surface reflects light at the exact angle that it strikes it. Reflected light rays go in the same direction over a flat surface. Specular reflection is the term for this. Reflected light rays disperse in all directions over a rough surface. Diffuse reflection is the term for this. When light strikes an item, it reflects in many different ways, which is known as diffuse reflection. When the surface is rough, something happens. The majority of what we see is due to light reflected from a source. When you look at a bird, for example, light has bounced off of it and travelled in virtually all directions. If any of the light gets into your eyes, it strikes the retina at the rear. An electrical signal is sent to your brain, which is translated into a picture by your brain. The angle of incidence is the angle at which light strikes a reflecting surface, while the angle of reflection is the angle at which light bounces off a reflecting surface. Imagine a perfectly straight line at a right angle to the reflecting surface (this imaginary line is termed ‘normal’) if you wish to measure these angles.
When the angle of incidence and the angle of reflection are measured against the normal, the angle of incidence and the angle of reflection are identical. It’s simple to demonstrate that the angle of reflection is the same as the angle of incidence using a flat mirror. Water is a reflecting surface as well. Because the reflecting surface of a lake or sea is relatively flat, the reflection of the landscape is excellent when the water is very calm. The reflection becomes distorted if there are ripples or waves in the water. This is because the reflecting surface is no longer flat and may contain wind-induced humps and troughs. Mirrors that behave like humps or troughs may be made, and they can be highly helpful due to the varied ways they reflect light. Reflecting telescopes, which employ concave mirrors, are a type of astronomical telescope. The mirrors concentrate a large amount of light from distant sources into a considerably smaller viewing area, allowing the user to see things and events in space that would otherwise be undetectable to the human eye. Light rays move in a straight path towards the mirror and are reflected inwards to meet at a location known as the focal point. Concave mirrors are ideal for make-up mirrors because they may distort the image and make it appear larger. Car headlights and satellite dishes both benefit from this concave form.
Refraction of Light
The bending of light (as well as water, sound, and other waves) when it travels from one transparent medium into another is known as refraction. Even our eyes are reliant on light bending. When light travels at an angle into a material having a differing refractive index, it refracts (optical density). A change in speed causes this shift in direction. How far can light bend? The magnitude of bending is determined by two factors: Change in speed – a material that causes light to refract (bend) more will cause it to speed up or slow down more. Angle of the incident ray – the amount of refraction will be more visible if the light enters the substance at a larger angle. On the other hand, if light enters the new substance from the front (at 90 degrees to the surface), the light will slow down but not change direction.
All angles are calculated using a 90-degree imaginary line placed on the surface of the two substances. The normal is a dotted line that is drawn as a straight line. When light passes through a material with a higher refractive index than air (such as glass), it slows down. When light enters a material with a lower refractive index (for example, from water to air), it accelerates. The light deviates from the straight line. When light enters a material with a greater refractive index, it will slow down and shift direction more. A lens is nothing more than a bent piece of glass or plastic. There are two types of lenses available. The centre of a biconvex lens is thicker than the borders. This is the type of lens that is used in magnifying glasses. A focal point can be created by focusing parallel beams of light.
Can you answer the question: No matter how far you stand from a spherical mirror, your image appears erect. The mirror is likely to be?