A small planar mirror is attached to a thin vertical wire so that the mirror is parallel to a wall $1.0 \mathrm{m}$ away. A horizontal scale is mounted flat on the wall opposite the mirror, whose center is directly opposite the zero mark on the scale. A horizontal laserbeam reflects off the mirror and hits the scale at $5.0 \mathrm{cm}$ left of zero. The mirror is then rotated through an angle $\alpha$ and the beam-scale spot of light moves left an additional $15.0 \mathrm{cm} .$ Find $\alpha$.
Added by James R.
Step 1
Initially, the laser beam hits the scale at 5.0 cm left of zero. Since the mirror is parallel to the wall, the angle of incidence is equal to the angle of reflection. Let's call this angle $\theta$. Show more…
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