A student investigates the refraction of a ray of light passing through a rectangular transparent block ABCDABCDABCD to determine its refractive index nnn.
The student sets up the experiment with an angle of incidence θ=45∘\theta = 45^\circθ=45∘ at the first surface ABABAB. After tracing the paths of the incident and emergent rays, they record the following measurements:
Answer the following questions:
Calculate the ratio dl\frac{d}{l}ld.
Suggest how the student can adapt this experiment to check if this ratio dl\frac{d}{l}ld is reproducible.
Suggest one potential source of inaccuracy in this optical ray-tracing experiment, even if it is performed with care.
The refractive index nnn of the block can be calculated using the formula:
n=0.707×lL n = 0.707 \times \frac{l}{L} n=0.707×LlCalculate the value of nnn to 2 decimal places.
216 exam-style questions on CIE IGCSE Physics 3.2 Light, covering 3.2.1a Reflection of light, 3.2.1b Images in a plane mirror, 3.2.2 Refraction of light, 3.2.2a Refraction of light, 3.2.2b Total internal reflection, 3.2.2c Refractive index and critical angle, 3.2.2d Optical fibres, 3.2.3a Converging and diverging lenses, 3.2.3b Ray diagrams and the nature of images, 3.2.3c Virtual images and the magnifying glass, 3.2.3d Correcting long-sightedness and short-sightedness, and 3.2.4 Dispersion of light. Each one has a worked solution and a mark scheme showing where the marks go.