IGCSE Physics Quiz

Light Behavior: Reflection & Refraction

Syllabus: 3.2.2 | Papers: 2 (MCQ), 4 (Structured), 6 (Practical)

📋 PAPER 2: Multiple Choice Questions

Choose the correct answer. Click "Check" to reveal detailed explanations and common traps.

Question 1: You stand 3m from a plane mirror. What is the distance between you and your image?

3m6m1.5m0m

Question 2: Light travels from air into glass (n=1.5) at an angle of incidence of 30°. What happens to the light ray?

Bends away from the normalBends towards the normalContinues straightReflects completely

Question 3: What is the critical angle?

The angle at which light is completely absorbedThe angle of incidence where the angle of refraction is 90°The angle at which light splits into colorsThe angle of maximum brightness

Question 4: Which TWO conditions are necessary for Total Internal Reflection to occur?

Light travels from less dense to more dense mediumLight travels from more dense to less dense mediumAngle of incidence is less than the critical angleAngle of incidence is greater than the critical angle

Question 5: A light ray enters a glass block. Which statement about the speed of light is correct?

Speed increases because glass is denserSpeed decreases because glass is denserSpeed remains constant in all materialsSpeed increases because of reflection

📝 PAPER 4: Structured Questions

Show full working. Click "Show Mark Scheme" to see keywords and common errors.

Question 1: Light travels from air into a glass block

(a) Light hits the glass at an angle of incidence of 30°. The refractive index of glass is 1.5. Calculate the angle of refraction.[3 marks]

Write your answer here (on paper or mentally)...

(b) Explain why the light ray bends towards the normal when entering the glass.[2 marks]

Write your answer here (on paper or mentally)...

Question 2: Total Internal Reflection in optical fibres

(a) State the two conditions necessary for Total Internal Reflection to occur.[2 marks]

Write your answer here (on paper or mentally)...

(b) The critical angle for glass-air boundary is 42°. A light ray in glass hits the boundary at 50°. Describe what happens to the light ray.[2 marks]

Write your answer here (on paper or mentally)...

🔬 PAPER 6: Alternative to Practical

Analysis, measurement reading, and practical technique questions.

Paper 6: Alternative to Practical - Measuring Refractive Index

Context: A student investigates the refractive index of a glass block by measuring angles of incidence and refraction.

Diagram showing light ray entering glass block

(a) The student measures the angle of incidence as 40° using a protractor. State one way to improve the accuracy of this measurement.[1 mark]

Write your answer here (on paper or mentally)...

(b) The student records these results: Angle of incidence i: 20°, 30°, 40°, 50°, 60° Angle of refraction r: 13°, 19°, 25°, 30°, 35° Calculate the refractive index using the measurements at i = 40°.[3 marks]

Write your answer here (on paper or mentally)...

(c) The student notices that when the angle of incidence is 60°, the refracted ray is very faint. Suggest why this happens.[2 marks]

Write your answer here (on paper or mentally)...

📚 Exam Technique Summary

• Formula Triangle: n₁ sin i = n₂ sin r (Air is n=1.0, Glass is typically n=1.5)

• Direction Rule: Dense → Less Dense = bends AWAY from normal; Less Dense → Dense = bends TOWARDS normal

• TIR Checklist: (1) Dense to Less Dense, (2) i > critical angle

• Critical Angle: The angle where r = 90° (sin c = 1/n)

• Unit Police: Angles in DEGREES (not radians unless specified)

• Mirror Distance Trap: Image distance from YOU = 2× distance to mirror

Sign In to Keep Going