A student determines the refractive index nnn of a transparent rectangular plastic block using a ray-tracing method.
In one trial, using an angle of incidence i=40∘i = 40^\circi=40∘, the student measures the following lengths:
The formula relating the refractive index nnn to these lengths for i=40∘i = 40^\circi=40∘ is:
n=0.64ba n = \frac{0.64b}{a} n=a0.64bCalculate the value of the refractive index nnn. Give your answer to 2 or 3 significant figures.
The student expected the values of refractive index obtained at different angles of incidence to be identical, but they differ slightly. State two experimental difficulties or sources of error in this type of pin-tracing experiment that could explain this difference.
Which of the following is the most sensible precaution to take during this experiment to obtain highly reliable results?
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.