A wavefront of light meets the boundary between air and glass at an angle.
Which statement explains why the light changes direction towards the normal?
One side of the wavefront slows down first, so the wavefront swings round
One side of the wavefront speeds up first, so the wavefront swings round
The whole wavefront slows down at once, so it turns towards the normal
The frequency of the wavefront falls, so it turns towards the normal
51 exam-style questions on OCR GCSE Physics 5.3 Wave interactions, covering 5.3.1 Wavelength and how substances affect waves, 5.3.2 Wave velocity in different substances, 5.3.3 Convex and concave lenses, 5.3.4 Ray diagrams for reflection and refraction, and 5.3.5 Colour, absorption and reflection. Each one has a worked solution and a mark scheme showing where the marks go.