Waves Exam Questions for IGCSE Physics

This guide covers the question types in the waves section of IGCSE Physics.

Question type 1: Wave equation calculations

Use v = f x lambda to calculate speed, frequency or wavelength.

Worked example: A wave has a frequency of 500 Hz and a wavelength of 0.68 m. Calculate its speed.

v = f x lambda = 500 x 0.68 = 340 m/s.

Question type 2: Reflection and refraction diagrams

Draw accurate ray diagrams showing the incident ray, normal, reflected/refracted ray and the angles. For reflection: angle i = angle r. For refraction: light bends towards the normal when entering a denser medium.

Question type 3: Total internal reflection

State the two conditions: light must travel from a denser to a less dense medium, and the angle of incidence must be greater than the critical angle. Draw a diagram.

Question type 4: Electromagnetic spectrum questions

Place the types of electromagnetic radiation in order. State one use and one hazard for each. Know that all EM waves travel at 3.0 x 10^8 m/s in a vacuum.

Question type 5: Sound questions

Describe how sound waves travel (longitudinal, need a medium). Explain the relationship between amplitude and loudness, frequency and pitch. Calculate the speed of sound using distance and time measurements.

Question type 6: Snell’s law (Extended)

Use n = sin i / sin r to calculate the refractive index or an angle. Use n = 1 / sin c to find the critical angle.

Worked example: Light enters glass at an angle of incidence of 45 degrees. The angle of refraction is 28 degrees. Calculate the refractive index.

n = sin 45 / sin 28 = 0.707 / 0.469 = 1.51.

Practice approach

Focus on wave equation calculations and ray diagram accuracy. These earn the most marks.