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In today's lab we will be studying reflection.
Reflection off a mirror is called specular reflection.
In specular reflection, the angle of incidence is equal to the angle of reflection.
These angles are measured from the light's path to the normal or a line drawn perpendicular to the mirror's surface.
We can picture the light being emitted by a source as a group of rays that spread out in all directions.
The rays that hit the mirror will be reflected at the same angle as their incident angle.
If we trace these rays behind the mirror, shown with dashed lines,
the place where they meet is where the virtual image will form.
This is the image that we see when we look into a mirror.
Let's apply this to the reflection of some coins in a mirror.
Initially the cameras is placed so that we cannot see the virtual image of the coins in the mirror.
We can only see objects that are directly in front of the mirror.
As the camera is rotated the image of the coin comes into view.
If we consider the light scattered by a single point on the object
we can draw a path from that point on the object
bouncing off the mirror and into the camera which is just below the right hand corner of the screen.
The light scattering off the coin is an example of diffuse reflection or scattering.
The light from the light source will bounce off the rough surface in all different directions.
There's no virtual image in this case as the virtual rays, represented here as dashed lines, do not converge.
To study the law of reflection you will use a ray table and a light source that you will mount in an optics bench.
To turn on the light source connect the power cable to the input jack on the side.
By rotating the dial on the light source you can obtain four different types of beams.
For this experiment we will use a single slit in front of the light source so that we have one beam of light
We will then place the mirror on the ray table
The ray table's angle markings will allow you to measure the angle of incidence and reflection
for the incoming and outgoing beams.
By rotating the ray table while keeping the beam of light steady,
you can change the angle of incidence of the light on the mirror.
Does the law of reflection hold?