A student wants to find the refractive index of a semicircular glass block using the critical angle method.
Describe how the student should set up the apparatus, specifically explaining how the ray of light should be directed relative to the curved and flat faces of the block.
State what specific angle measurement the student must record and describe how they know this measurement represents the critical angle.
Explain how the student should use their measurement to determine the refractive index of the glass block.
The diagram shows a section through a right-angled glass prism with angles of 90∘90^\circ90∘, 45∘45^\circ45∘, and 45∘45^\circ45∘. A horizontal ray of light is incident perpendicularly on the vertical flat face of the prism.
The critical angle for this glass is 41∘41^\circ41∘. Describe the path of the ray after it hits the slanted surface of the prism, including calculations of relevant angles, and state where and how it emerges from the prism.
What happens to the speed of the light ray as it enters the glass prism?
