Inclined Plane Mirrors and Parallel Reflected Rays

When two plane mirrors are inclined at a certain angle, the reflection of light from the mirrors follows specific laws and principles. In this case, we have two plane mirrors inclined at 60 degrees to each other, and a ray of light incident on one mirror parallel to the other. Let's explore how the reflected ray from the second mirror becomes parallel to the first mirror.

Law of Reflection

Before diving into the specific scenario, it's important to understand the law of reflection. According to this law, the angle of incidence (θi) is equal to the angle of reflection (θr). The incident ray, reflected ray, and the normal to the mirror all lie in the same plane.

Ray Incident on the First Mirror

Let's consider a ray of light incident on the first mirror parallel to the second mirror. This incident ray can be represented by a line perpendicular to both the mirrors, as shown in the diagram.

Reflection from the First Mirror

According to the law of reflection, the angle of incidence is equal to the angle of reflection. Since the incident ray is parallel to the second mirror, the angle of incidence is 0 degrees. Therefore, the angle of reflection from the first mirror is also 0 degrees.

Incident Ray on the Second Mirror

The reflected ray from the first mirror becomes the incident ray on the second mirror. As the first reflected ray is parallel to the second mirror, the incident angle on the second mirror is also 0 degrees.

Reflection from the Second Mirror

Again, the angle of incidence is equal to the angle of reflection. Since the incident angle is 0 degrees, the angle of reflection from the second mirror is also 0 degrees.

Parallel Reflected Ray

Since the reflected ray from the second mirror has an angle of reflection of 0 degrees, it means that the reflected ray is parallel to the second mirror. And since the first reflected ray was parallel to the second mirror, it implies that the reflected ray from the second mirror is also parallel to the first mirror.

Conclusion

In summary, when two plane mirrors are inclined at 60 degrees and a ray of light is incident on one mirror parallel to the other, the reflected ray from the second mirror becomes parallel to the first mirror. This is due to the laws of reflection, which state that the angle of incidence is equal to the angle of reflection.