Edexcel IGCSE Physics 3.22 Critical Angle Equation Questions

For a material with refractive index n, calculate its critical angle using c = sin⁻¹(1/n). To find n from c, use n = 1/sin c; report c in degrees.

Syllabus
First assessment 2019
Course
Physics 4PH1

Exam points

  • state or rearrange sin c = 1/n for critical angle and refractive index questions
  • calculate c from a given refractive index using sin^-1 and give the angle in degrees
  • calculate n from a given critical angle, keeping suitable significant figures

Edexcel IGCSE Physics 3.22 Critical Angle Equation Questions question 1

[Maximum number: 4]

This question is about refraction.

Question (a)

(a)

The torch is moved below the surface of the water. Light from the torch is incident on the water surface at an angle greater than the critical angle.

[ 4 ]

Question (i)

(i)

State the formula linking critical angle and refractive index.

[ 1 ]

Question (ii)

(ii)

Calculate the critical angle of water.

Assume the refractive index of water is 1.3

[ 3 ]
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