The diagram shows a road safety worker examining a raised cat's-eye marker. A car headlamp shines on one face of the marker. Inside, two reflective faces me...
Question 1 Report
The diagram shows a road safety worker examining a raised cat's-eye marker. A car headlamp shines on one face of the marker. Inside, two reflective faces meet at a right angle. The returned light is seen by the driver even when rain makes the road surface dark. The worker compares the marker with a flat strip of reflective tape.
(a) Describe the path of the ray inside the marker. [2]
(b) Explain why the driver receives light back from the marker. [2]
(c) Give one advantage of this marker over a plane mirror fixed at one angle. [2]
Answer Details
(a) The ray reflects from one internal face [1] and then reflects from the second face. [1]
(b) The two reflections reverse the ray direction, returning it towards its source. [1] Therefore reflected light reaches the driver. [1]
(c) The marker works for a range of car positions or directions. [1] A plane mirror would need accurate alignment to return light to the driver. [1] This is why a corner reflector is more reliable for road visibility.
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