Why light bends at a boundary, the path of a ray through a rectangular block and a prism, dispersion of white light, and calculating refractive index with Snell’s law.
5 narrated scenes. Press play, listen and read along — the points appear as they are explained. Use ‹ Prev / Next › or the scene bar to jump to any scene.
A straw in a glass of water looks bent, and a swimming pool seems shallower than it really is. Both are refraction.
Narration uses your device’s built-in voice. No sound? Switch to “Captions only” — the captions advance on their own.
Change the angle of incidence and the refractive index.
Copy these into your notebook in your own words — that is how they stick.
Change of direction caused by a change of speed at a boundary.
Light slows down and bends towards the normal.
Light speeds up and bends away from the normal.
Emergent ray parallel to incident ray but laterally displaced.
Bends light towards its base; white light disperses into a spectrum.
Red (least bent) to violet (most bent).
n = sin i ÷ sin r (air to medium); glass ≈ 1.5; water ≈ 1.33.
Does not change; speed and wavelength change.
3 quick games on this lesson. Earn XP and badges as you play — your best score for each game is saved. Games are for practice and do not change your exam readiness. More games in the Physics Arcade.
8 items modelled on real CSEC Paper 1 questions. Choose one answer for each, then check. Aim for 80% or better. Work each item on paper first.
Write full answers, then reveal the mark scheme and tick the points you earned (15 marks in total). Show all your working — method marks count. Your answers are saved on this device.
Question 1 [15 marks]
A ray of light passes from a glass block into air. The ray makes an angle of 25° with the normal in the glass and 39° with the normal in the air.
(a) (a) Define refraction. [2]
(b) (b) Draw a diagram of the ray passing from glass into air, and label the normal and the angles. [4]
(c) (c) Calculate the refractive index of the glass. [3]
(d) (d) State why the ray bends away from the normal. [2]
(e) (e) State what happens to the frequency of the light as it enters the air. [1]
(f) (f) White light is passed through a glass prism. Describe and explain what is observed. [3]
Find these in your own past-paper booklets for extra timed practice. Items above are written in the style of these papers; any adapted from a specific question say so.