The ray that comes back from a surface after the reflection is known as ______.
A reflected ray
Reflection: Understanding Reflected Rays
In the study of light and optics, when a ray of light strikes a surface and bounces back, this phenomenon is called reflection. The ray that originates from a source and travels towards the surface is known by a specific name, and similarly, the ray that bounces back also has a distinct name.
Light Rays and Reflection Basics
To understand the ray that comes back from a surface after reflection, let's first define the key terms involved in the process of light reflection:
- Incident Ray: This is the ray of light that approaches and strikes a surface. Think of it as the incoming ray.
- Point of Incidence: This is the exact point on the surface where the incident ray strikes.
- Normal: This is an imaginary line drawn perpendicular (at 90 degrees) to the surface at the point of incidence. It helps us measure angles.
- Reflected Ray: This is the ray of light that bounces back from the surface after reflection. It's the outgoing ray.
- Angle of Incidence ($\theta_{i}$): This is the angle between the incident ray and the normal.
- Angle of Reflection ($\theta_{r}$): This is the angle between the reflected ray and the normal.
The Law of Reflection
The behavior of light during reflection is governed by the Law of Reflection, which states:
- The incident ray, the reflected ray, and the normal to the surface at the point of incidence all lie in the same plane.
- The angle of incidence ($\theta_{i}$) is equal to the angle of reflection ($\theta_{r}$). That is, $\theta_{i} = \theta_{r}$.
This law explains how the reflected ray behaves relative to the incident ray and the surface.
Analyzing the Given Options
Let's examine the options provided in the context of the question: "The ray that comes back from a surface after the reflection is known as ______."
| Option | Explanation |
|---|---|
| A reflected ray | This term precisely describes the ray of light that bounces off a surface after reflection. It is the correct terminology used in optics. |
| An x-ray | X-rays are a type of electromagnetic radiation with very short wavelengths. While they can be reflected, "X-ray" is a type of ray, not a general term for a ray that has undergone reflection. |
| An incident ray | An incident ray is the ray that approaches and strikes the surface, not the one that comes back after reflection. |
| An alpha ray | Alpha rays (or alpha particles) are positively charged particles emitted during radioactive decay. They are not light rays and are unrelated to the concept of light reflection from a surface in this context. |
Conclusion
Based on the definitions and the principles of reflection, the ray that comes back from a surface after reflection is universally known as a reflected ray. This term clearly distinguishes it from the incident ray and other types of rays.
Important Questions from Wave
Which of the following is correct?
I. Sound is a mechanical wave
II. Sound wave does not need any medium to propagate
At a particular temperature, sound propagates in ______ at the fastest speed .
The atmospheric green house effect is produced mainly by the absorption and re-emission of:
Which of the following are examples of electromagnetic waves?
a. Television waves
b. Ultraviolet rays
c. X-rays
d. Sun rays
When light passes from one medium into another medium, then the physical property which does not change is
