3.2.1 Reflection of light

CORE:

• Define and use the terms normal, angle of incidence and angle of reflection
• Describe the formation of an optical image by a plane mirror, and give its characteristics, i.e. same size, same distance from mirror, virtual
• State that for reflection, the angle of incidence is equal to the angle of reflection; recall and use this relationship

EXTENDED/SUPPLEMENT:

• Use simple constructions, measurements and calculations for reflection by plane mirrors

3.2.2 Refraction of light

CORE:

• Define and use the terms normal, angle of incidence and angle of refraction
•  Describe an experiment to show refraction of light by transparent blocks of different shapes
•  Describe the passage of light through a transparent material (limited to the boundaries between two media only)
•  State the meaning of critical angle
• Describe internal reflection and total internal reflection using both experimental and everyday examples

SUPPLEMENT:

• Define refractive index, n, as the ratio of the speeds of a wave in two different regions
• Recall and use the equation n = sini sinr 8 Recall and use the equation n = 1/ sinc
•  Describe the use of optical fibres, particularly in telecommunications

3.2.3 Thin lenses

CORE:

• Describe the action of thin converging and thin diverging lenses on a parallel beam of light
• Define and use the terms focal length, principal axis and principal focus (focal point)
•  Draw and use ray diagrams for the formation of a real image by a converging lens
•  Describe the characteristics of an image using the terms enlarged/same size/diminished, upright/inverted and real/virtual
• Know that a virtual image is formed when diverging rays are extrapolated backwards and does not form a visible projection on a screen Supplement
•  Draw and use ray diagrams for the formation of a virtual image by a converging lens
•  Describe the use of a single lens as a magnifying glass
• Describe the use of converging and diverging lenses to correct long-sightedness and shortsightedness

3.2.4 Dispersion of light

CORE:

• Describe the dispersion of light as illustrated by the refraction of white light by a glass prism
• Know the traditional seven colours of the visible spectrum in order of frequency and in order of wavelength Supplement
• Recall that visible light of a single frequency is described as monochromatic