An incident ray is reflected normally by a plane mirror onto a screen where it forms a bright spot. The mirror and screen are parallel and 1m apart. If the mirror is rotated through 5o, calculate the displacement of the spot
- 8.7cm
- 10.0cm
- 15.4cm
-
17.6cm
The correct answer is: D
Explanation
From the diagram above,
Tan\(\theta\) = \(\frac{\text{d}}{100}\)
Tan10º = \(\frac{\text{d}}{100}\)
d = 100 x Tan 10º = 100 x 0.1763 ≈ 17.6cm.