The laws of reflection, measuring angles from the normal, how a plane mirror forms a virtual image, and locating images by ray plotting and the no-parallax method.
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.
When you look in a mirror, your “twin” seems to stand behind the glass. That twin is not really there — it is a virtual image, and ray diagrams show exactly where it is.
Narration uses your device’s built-in voice. No sound? Switch to “Captions only” — the captions advance on their own.
Copy these into your notebook in your own words — that is how they stick.
Line at 90° to the surface at the point of incidence; angles are measured from it.
Angle of incidence = angle of reflection.
Incident ray, reflected ray and normal are in the same plane.
Virtual, upright, same size, laterally inverted, as far behind the mirror as the object is in front.
Cannot be formed on a screen; rays only appear to come from it.
Dashed rays behind the mirror; solid rays in front.
Pin and image stay lined up as the head moves.
Rough surfaces scatter light in all directions.
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 student investigates reflection of light from a plane mirror using a ray box and a protractor.
(a) (a) State the two laws of reflection. [2]
(b) (b) A ray strikes the mirror making an angle of 25° with the surface. Calculate the angle of reflection. [3]
(c) (c) List three characteristics of the image formed in a plane mirror. [3]
(d) (d) A boy stands 2.5 m from the mirror. State the distance from the boy to his image. [2]
(e) (e) Describe the no-parallax method to find the position of the image of a pin O. [4]
(f) (f) State one use of a plane mirror in a periscope. [1]
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.