The light ray arrives perpendicular to the plane of the mirror.
The answer depends on knowing what the plane mirror hhas a 20-degree angle relative to!
The perpendicular to a plane mirror is a line that is at a 90-degree angle to the mirror's surface. It is important for understanding the reflection of light rays off the mirror's surface, as the angle of incidence is equal to the angle of reflection with respect to this perpendicular line.
The similarity of the two is that if.... example: if you shined a flashlight at a 30 degree angle on a mirror it will reflect and show as a 30 degree angle on the other side. They are equal.
You have given the glancing angle as 30 degree. So the angle of incidence = 90-30 = 60 deg As i = r by the law of reflection the angle of reflection = 60 deg
The angle of incidence is equal to the angle of reflection in a plane mirror. This is known as the law of reflection, which states that the angle at which a light ray hits a mirror is equal to the angle at which it bounces off the mirror.
angle of incidence
The angle of incidence is defined as the angle between the incoming light and the line that is normal to the surface at the point where the light 'hits' the surface. The reflectrion angle is the same as the incidence angle. If the angle between the incident ray and the mirror ray is 50, then the angle of incidence is half of this. That is, 25 degrees.
reflection.
When light with normal incidence strikes a mirror, it reflects back at the same angle in the opposite direction. This is known as specular reflection, where the angle of incidence is equal to the angle of reflection.
The angle between the mirror and the normal is called the angle of incidence. It is the angle formed between the incident ray (incoming light ray) and the normal (a line perpendicular to the surface of the mirror) at the point of incidence.
If a light ray is reflected from a flat mirror with a reflection angle of 55o then the angle of incidence was also 55o. When reflecting from a mirrored surface, the angle of incidence equals the angle of reflection.
90 degrees is the largest possible angle of incidence because it is then parallel to the face of the mirror and is grazing the mirror.