Answer:
Thus, the smallest angle of incidence with respect to the top mirror, such that the laser beam hits only one of the mirrors = 70.6° to the normal
the smallest angle of incidence with respect to the top mirror, such that the laser beam hits each mirror only once = 62.2° to the normal
Step-by-step explanation:
If the laser beam is directed at the top mirror from the left edge of the bottom mirror; i.e the laser beam is shone from the left end of the plane; The we have:
since the two plane mirror forma the 17.0 cm length and provided it hits only one mirror



Thus; i = (90° - 19.4°)
i = 70.6° to the normal
Thus, the smallest angle of incidence with respect to the top mirror, such that the laser beam hits only one of the mirrors = 70.6° to the normal
b)
provided that the laser beam hits each mirror only once.


Thus; i = (90° - 27.8°)
i = 62.2° to the normal
Thus, the smallest angle of incidence with respect to the top mirror, such that the laser beam hits each mirror only once = 62.2° to the normal