Light

Reflection, refraction, refractive index and the image characteristics of converging lenses.

Learning goals

Use the normal, angle of incidence and angle of reflection
Apply the law of reflection in constructions, measurements and calculations
Use the normal, angle of incidence and angle of refraction
Apply sin i divided by sin r as a constant for a fixed pair of media
Define refractive index as vacuum light speed divided by medium light speed
Describe how a thin converging lens acts on a light beam
Define the focal length of a converging lens
Describe lens images as real or virtual, magnified or diminished, and upright or inverted

G3 Science (Physics) · Topic 11

Begin with the complete topic lesson. Then try a short check, use the feedback to review one idea and come back later for another attempt.

Reflection, refraction, refractive index and the image characteristics of converging lenses.

Check the required topic capabilities and get focused practice for ideas that need another look.

Measure incidence, reflection and refraction angles from the normal, not from the surface.
For reflection, i = r; for refraction through a fixed pair of media, sin i / sin r is constant.
Light bends towards the normal when it slows down and away from the normal when it speeds up.
Refractive index n = c/v, so a larger index means a smaller light speed in the medium.
Describe a lens image independently as real or virtual, upright or inverted, and magnified or diminished.

Light is Topic 11 in K326 / K327 Physics component · 2027.

The lesson and questions stay at the depth required for this course.

Reviewed 9 Aug 2026

Course and syllabus information