A convex traffic mirror of diameter is mounted at a road junction to allow drivers on…
PHYSICS · Multi-part · CBSE · Physics · Light — Reflection and Refraction · Light — Reflection and Refraction
Problem
A convex traffic mirror of diameter 30cm is mounted at a road junction to allow drivers on one road to see vehicles approaching along a side road. The centre of the mirror is located 2.0m above the level of the roads. A car of height 1.5m is travelling along the side road at a distance of 20m from the mirror and is on the mirror’s principal axis.
(a) If the mirror has a focal length of 50cm, calculate the position of the image of the top of the car.
(b) Determine the apparent height of the car’s image in the mirror.
(c) Assuming small-angle approximation, estimate the linear width of road (measured perpendicular to the principal axis) that can be observed in the mirror at the distance of 20m.
(d) Discuss whether increasing the diameter of the mirror or decreasing its focal length is more effective in enlarging the observed road width, supporting your answer with suitable reasoning or calculations.