Final answer:
The reflected angle θ2 is equal to the incident angle θ1 due to the Law of Reflection, and when light reflects off two perpendicular mirrors, the outgoing ray is parallel to the incoming ray.
Step-by-step explanation:
The Law of Reflection states that the angle of reflection (θ2) is equal to the angle of incidence (θ1). This means that when light strikes a mirror at an angle θ1, it reflects off the mirror at the same angle θ2 such that θ2 = θ1. When light reflects from two mirrors that meet at a right angle, the outgoing ray will be parallel to the incoming ray, according to the law of reflection, because the two consecutive reflections each change the direction of the ray by the same angle, effectively rotating the ray by a total of 180 degrees, which makes it parallel to the original direction of incidence.
In summary, if the light strikes the first mirror at an angle θ1, the reflected angle θ2 in terms of θ1 is simply θ2 = θ1.