What is the angle of incidence of a ray if the reflected ray is at an angle of 90° to the incident ray?
Solution and Explanation
We know that angle of incident ray is equal to angle of reflected ray.
⇒ ∠𝑖= ∠𝑟
But it is given that
∠𝑖+ ∠𝑟=90°
⇒∠𝑖+ ∠𝑖=90°
⇒2∠𝑖=90°
⇒∠𝑖=90°/2
⇒∠𝑖=45°
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Concepts Used:
Reflection of Light
Reflection of light is the process by which light waves bounce off a surface when they encounter it. It is a fundamental phenomenon that plays a crucial role in our everyday experiences with light and vision.
When light waves strike a surface, three possible outcomes can occur: absorption, transmission, or reflection. In the case of reflection, the light waves are neither absorbed nor transmitted but instead are redirected back into the original medium.
The angle of incidence, which is the angle between the incident light ray and the perpendicular to the surface, is equal to the angle of reflection, which is the angle between the reflected light ray and the perpendicular to the surface. This relationship is described by the law of reflection.
The law of reflection states that the incident ray, the reflected ray, and the normal (perpendicular) to the surface at the point of incidence lie on the same plane. Additionally, the angle of incidence is equal to the angle of reflection.
The reflective properties of a surface depend on its smoothness and nature. A smooth, polished surface, such as a mirror, exhibits regular or specular reflection, where light waves are reflected in a well-defined direction, resulting in a clear image. On the other hand, a rough or uneven surface exhibits diffuse reflection, where light waves are scattered in various directions, leading to a blurred or scattered reflection.
The reflection of light is utilized in numerous practical applications. Mirrors are used for reflection in optics, photography, and everyday objects like mirrors in households and vehicles. Reflective surfaces are employed in optical systems, such as telescopes, microscopes, and laser devices. The understanding of light reflection is also vital in architectural design, where the reflection of natural light is harnessed to enhance lighting and energy efficiency in buildings.
Overall, the reflection of light is a fundamental phenomenon that enables us to perceive the world around us, and its principles find application in various scientific, technological, and practical domains.