Question

Two plane mirrors are facing each other. They are parallel, 6 cm apart, and 24 cm in length, as the drawing indicates. A laser beam is directed at the top mirror from the left edge of the bottom mirror. What is the smallest angle of incidence with respect to the top mirror, such that the laser beam hits the mirrors in each way

Answer 1

Answer:

86degrrss

Explanation:

tan L =BC/AB

= 3/12 = 1/4

L= tan^-1 0.25

=4.0 degrees

= 90-4= 86degrees

Answer 2

Answer: 33.69 degrees

Explanation:

Given

Distance between the two mirrors, = 6 cm

Length of the two mirrors, = 24 cm

Assuming the laser is shone from just clear of the left edge of the bottom mirror,

a)

Tan L = (O/A)

Tan L = (6 / 12)

Tan L = 0.5

L = Tan^-1 (0.5)

L = 26.57 degrees

(90 - 26.57) = 63.43 deg. to the normal.

Tan L = (6 / [24/6])

Tan L = (6 / 4)

Tan L = 1.5

L = Tan^-1 (1.5)

L = 56.31 degrees

(90 - 56.31) = 33.69 deg. to the normal.

Thus, the angle at which, with respect to the mirror, the laser beam hits the mirrors in each way is 33.69 degrees