How Does a Corner Reflector Work to Reflect Light Back Along Its Incident Path?

[shaiqbashir]

Hi!

Well can u help me in this problem. it is related to a device called Corner Reflector.

" A corner reflector is formed by three mutually perpendicular reflecting surfaces. Show that a ray of light incident upon the corner reflector (striking all three surfaces) is reflected back along a line parallel to the line of incidence.(Hint: Consider the effect of a reflection on the components of a vector describing the direction of the light ray). The Apollo mission placed this type of reflector on the surface of the moon in 1969."

Please help me in this problem, i just don't know how to solve it. i have only one days left for my test. Plz Help me in detail so that i can get it understood.

"Thanks in advance"

 

[HallsofIvy]

Consider the case where the light hits only two of the surfaces first.

 

[thepatientmental]

Hi there! I would be happy to help you with this problem. A corner reflector is a device that is commonly used in optics and is made up of three perpendicular mirrors. When a ray of light strikes this reflector, it is reflected back along a line parallel to the line of incidence, which is the path of the incoming light ray. This phenomenon is known as total internal reflection.

To understand this concept better, let's break it down step by step. First, imagine a ray of light approaching the corner reflector. This ray can be represented by a vector, with its direction and magnitude indicating the path and intensity of the light. Now, when this ray of light strikes the first mirror, it undergoes reflection according to the law of reflection, which states that the angle of incidence is equal to the angle of reflection. This means that the direction of the reflected ray will be exactly opposite to the direction of the incident ray.

Next, the reflected ray strikes the second mirror, which is perpendicular to the first one. Here, the same law of reflection applies, and the reflected ray will again be directed in the opposite direction. Finally, the reflected ray strikes the third mirror, which is perpendicular to both the first and second mirrors. Again, the law of reflection applies, and the reflected ray will be directed back along the same path as the incident ray, but in the opposite direction.

In summary, the three reflections result in the incident ray being reflected back along its original path, but in the opposite direction. This is why the reflected ray is parallel to the line of incidence. This phenomenon is utilized in various applications, such as in the Apollo mission where corner reflectors were used on the surface of the moon to reflect laser beams back to Earth for precise measurements.

I hope this explanation helps you understand the concept better. If you have any further questions, please feel free to ask. Best of luck on your test!