A technician calibrating an optical sensor directs a narrow laser ray into a removable rectangular glass cover at a non-zero angle to the normal. The ray emerges from the opposite face. With the cover in position, the technician traces its outline and marks two well-separated points on the incident ray and two on the emergent ray. The cover is then removed.
How should the technician reconstruct the path of the ray inside the glass?
Draw a smooth curve from the entry point to the exit point, bending gradually towards the normal.
Draw a line from the entry point along the normal, then join it to the emergent ray at the opposite face.
Draw a line through each pair of points to the outline, then join the entry and exit points with a straight line.
Draw a line from the entry point parallel to the incident ray until it reaches the opposite face.
84 exam-style questions on Edexcel GCSE Physics 5.2 The electromagnetic spectrum, covering 5.2.1 Electromagnetic waves and refraction in glass (core practical), 5.2.2 Groups of the electromagnetic spectrum, 5.2.3 Wavelength-dependent behaviour of EM waves, and 5.2.4 Velocities of EM waves in different substances. Each one has a worked solution and a mark scheme showing where the marks go.