The critical angle for a glass is 41 degrees. Calculate its refractive index.

Firstly we must remind ourselves of what is meant by critical angle. The critical angle is the angle of incidence beyond which rays of light passing through a denser medium to the surface of a less dense medium are no longer refracted but totally reflected (easily represented on a diagram).
So in our equation for refraction we can substitute in n2 = 1 (because air has a refractive index of 1) and 𝜃1 = 41. We also know that 𝜃2 = 90 degrees because it is the critical angle which is the point at which the angle of refraction is 90 degrees. sin90 = 1 so 𝑛1 sin 𝜃1 = 𝑛2 sin 𝜃2 becomes n1 x sin41 = 1. So the refractive index of the glass (n1) = 1/sin41 = 1.524. Because we have only been given information to two significant figures in the question, we leave our answer as 1.5.

Answered by Marnie S. Physics tutor

14368 Views

See similar Physics GCSE tutors

Related Physics GCSE answers

All answers ▸

A person swims from a depth of 0.5m to 1.7m below the surface of the sea. Denisty Sea Water = 1030 kg/m^3. g=Gravitational Field Strength = 9.8 N/kg. Calculate the change in pressure on the swimmer and give the unit.


PHYSICS A LEVEL Explain why, when a red giant becomes a white dwarf, it moves towards the lower left of the Hertzsprung-Russell diagram [2]


How many times further away from the pivot point of a seesaw does someone of double the weight have to sit in order for the it to balance?


How much work must be done on a 4.0kg frictionless trolley, to accelerate it from rest to a velocity of 5.0m/s?


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences