A researcher wants to determine the refractive index of a semicircular block made of a newly developed transparent polymer using the critical angle method.
Describe how the apparatus should be arranged, explaining specifically the required path of the ray of light relative to both the curved and flat faces of the block.
State which angle must be measured and describe how the researcher can confirm that this measurement corresponds exactly to the critical angle.
Write down the formula relating this critical angle to the refractive index of the polymer and explain how the refractive index is calculated from it.
The diagram shows a section through a right-angled isosceles glass prism with angles of 90∘,45∘, and 45∘90^\circ, 45^\circ, \text{ and } 45^\circ90∘,45∘, and 45∘. The hypotenuse face of the prism is vertical. A horizontal ray of light is incident perpendicularly on this vertical face.
The critical angle for this glass is 42∘42^\circ42∘. Describe the complete path of the ray inside and emerging from the prism, including calculations of the angle of incidence at each boundary it encounters.
What happens to the speed of the light ray as it enters the glass prism?
