If, in the direction of the reflected beam, a beam of light is sent from the illuminator, it will be reflected from the mirror and go in the direction in which the incident beam went in the previous experiment. The beams and angles are reversed. This property of the reflected and incident rays is called the reversibility (or reciprocity) of light rays.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.