Physics
Physics
Problem
A laser located at fires a beam along the -axis toward a small plane mirror positioned at . After reflection, the beam must strike a sensor at . All points lie in the same horizontal plane. What is the angle between the mirror’s normal and the direction? a) b) c) d)Intuitive explanation
The key is using the law of reflection: the angle of incidence equals the angle of reflection, both measured from the mirror's normal. Since the mirror sits at a fixed position, you need to find what angle its normal must have so that a ray coming from the laser bounces off and reaches the sensor. Think of it as finding the mirror's orientation such that the incoming and outgoing rays make equal angles with the normal—this is a constraint that uniquely determines the normal's direction.
Intuitive explanation
The key is using the law of reflection: the angle of incidence equals the angle of reflection, both measured from the mirror's normal. Since the mirror sits at a fixed position, you need to find what angle its normal must have so that a ray coming from the laser bounces off and reaches the sensor. Think of it as finding the mirror's orientation such that the incoming and outgoing rays make equal angles with the normal—this is a constraint that uniquely determines the normal's direction.