Question on the Law of Reflection

In summary, the law of reflection states that the angle of incidence and the angle of reflection are equal when a beam of light reflects on a horizontal surface. The third angle formed is supplementary to these two angles, adding up to 180 degrees. This is because the total angle formed within the two lines of the beam of light must equal 180 degrees. The equation 2A + X = 180 represents this concept, with A being the value of both the incidence and reflection angles and X representing the third angle. Additionally, the angles are typically measured with respect to the surface normal, not parallel to the surface.
  • #1
manofslate
3
0
The law of reflection states that the angle of incidence equals the angle of reflection.

In the event of a beam of light reflecting upon a horizontal surface, the incidence angle is 45 degrees (as a variable, 45 degrees will be represented by A).

The angle formed by the reflection will also be 45 degrees (demonstrating the law of reflection).

There is a third angle which has also been formed. If the line is horizontal (by horizontal, I mean that a perceived vertical auxiliary line could be drawn and intersect with the first line to form two right angles), then the total value should 180 degrees.

The values of the angles of reflection and incidence are equal, therefore I’ll refer to them both with the variable A. So, 2A is the value of both angles.

180 -2(45) = 90.

In between the two lines formed by the incidence and reflection of the beam of light, there exists a right angle (this surely must be the case because an additional ninety degrees is necessary to complete 180 degrees.

So, the third angle formed (with respect to the two angles formed by the reflecting beam of light) is summed up by the equation:

2A + X = 180

The variable X will be the remaining angle


Basically, if a reflective surface is horizontal, can this surface be viewable as the diameter of a circle, with a total angle measure of pi radians (180 degrees)?

If this is the case, then the angle in-between the angles formed by incidence and reflection must ensure that the total amount of degrees will equal 180 degrees, am I correct?

Sorry, it’s been a while since I’ve studied the law of reflection, but I’m still curious.

Oh, and forgive me if there are any fallacies. I'm only a sophomore in high school, and I really hastily scrawled this out.
 
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  • #2
Firstly, welcome to the forums!

Your understanding of the law of reflection is correct, except that angles in this context are conventionally taken with respect to the surface normal (not parallel to the surface).

I am also confused by this statement;

manofslate said:
Basically, if a reflective surface is horizontal, can this surface be viewable as the diameter of a circle, with a total angle measure of pi radians (180 degrees)?

Claude.
 
  • #3
Hey Claude,

Thanks for reading this. I didn't clarify on the aforementioned statement; mixing up on units and such. To make it simple, all of the angles formed by the reflecting light on the given surface are supplementary, correct? They must all total 180 degrees?
 
  • #4
manofslate said:
To make it simple, all of the angles formed by the reflecting light on the given surface are supplementary, correct? They must all total 180 degrees?
Only because you've assumed a flat surface. This would be true even if the angles of incidence and reflection were not equal. (Unless I missed your point.)
 
  • #5


I am glad to see your curiosity and understanding of the law of reflection. You are correct in your observations that the angle of incidence and the angle of reflection must add up to 180 degrees. This is because the reflective surface acts like a mirror, where the incident angle and the reflected angle are equal and opposite. This can be visualized as the diameter of a circle, where the two angles are the same length and add up to 180 degrees.

I would also like to add that the law of reflection is not limited to just horizontal surfaces. It applies to any surface, as long as it is smooth and flat. This is because light behaves in a predictable manner when it comes into contact with a smooth surface, and the angle of incidence will always equal the angle of reflection.

I encourage you to continue exploring and learning about the law of reflection, as it is an important concept in the study of optics and light. Keep asking questions and seeking answers, as that is the foundation of scientific inquiry. Best of luck in your studies!
 

FAQ: Question on the Law of Reflection

What is the Law of Reflection?

The Law of Reflection states that when a ray of light hits a reflective surface, the angle of incidence (the angle between the incoming ray and the normal to the surface) is equal to the angle of reflection (the angle between the reflected ray and the normal).

What is the difference between specular and diffuse reflection?

Specular reflection occurs when light bounces off a smooth surface, such as a mirror, at the same angle as it hits the surface. Diffuse reflection, on the other hand, occurs when light bounces off a rough surface in multiple directions.

How does the Law of Reflection apply to curved surfaces?

The Law of Reflection still applies to curved surfaces, but the angle of incidence and angle of reflection are measured at the point where the ray of light intersects the surface. This is known as the normal at that point.

What is the relationship between the angle of incidence and the angle of reflection?

The angle of incidence and the angle of reflection are always equal in accordance with the Law of Reflection. This means that if the angle of incidence increases, the angle of reflection will also increase by the same amount.

How does the Law of Reflection relate to the law of conservation of energy?

The Law of Reflection follows the law of conservation of energy, which states that energy cannot be created or destroyed, only transferred from one form to another. In the case of reflection, the energy of the incoming light ray is equal to the energy of the reflected light ray.

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