None. Degrees are a measurement of angle.
90
The angle of incident is 45 degrees. The incident and reflected ray have the same magnitude and if the sum of the magnitudes is 90 degrees the incident is 45 degrees.
If I understand the question correctly, then 0 degrees or 180 degrees.
The law of reflection: When a ray of light reflects off a mirror, the angle of the incidence ray is equal to the angle of the reflection ray. Therefore, an incidence ray of 45 degrees will have a reflection ray of 45 degrees. As both rays are equal, either side of the normal line, then adding both angles equals 45 + 45 = 90 degrees. The normal line is a line perpendicular to the surface of the mirror.
a ray
42 degrees
The angle of incident is 45 degrees. The incident and reflected ray have the same magnitude and if the sum of the magnitudes is 90 degrees the incident is 45 degrees.
42 degrees
it is 42 degrees
If I understand the question correctly, then 0 degrees or 180 degrees.
42 degrees
a ray
The law of reflection: When a ray of light reflects off a mirror, the angle of the incidence ray is equal to the angle of the reflection ray. Therefore, an incidence ray of 45 degrees will have a reflection ray of 45 degrees. As both rays are equal, either side of the normal line, then adding both angles equals 45 + 45 = 90 degrees. The normal line is a line perpendicular to the surface of the mirror.
The angle of incidence would be 90 degrees, so the angle of refraction is 0 degrees, as the light ray does not deviate.
The angle of reflection is 140/2 = 70 degrees. The angle of reflection is the same as the the same as the incident.
If the ray is incident at right angles to the reflection surface, angle of Incidence will be 90 degrees and so will be the angle of reflection. In such a case, the incident ray, the normal and the reflected ray coincide.
Either when they are both 0 degrees (the incident ray is perpendicular to the surface) or the refractive indices of the two media are the same.Either when they are both 0 degrees (the incident ray is perpendicular to the surface) or the refractive indices of the two media are the same.Either when they are both 0 degrees (the incident ray is perpendicular to the surface) or the refractive indices of the two media are the same.Either when they are both 0 degrees (the incident ray is perpendicular to the surface) or the refractive indices of the two media are the same.
It only happens when the incident ray is shone at 90 degrees. The refracted ray will then travel along the same path as the incident ray. This is known as total internal refraction.