Waves and Optics 21. Define amplitude, wavelength, frequency, and speed of a wave. (4 marks) 22. Explain the principle of superposition of waves. (3 marks) 23. Describe Young's double-slit experiment and its significance. (4 marks) 24. Calculate the speed of sound in air at 25C. (v = 331.4 m/s + 0.6 m/s/C * T) (2 marks) 25. Explain the Doppler effect and provide an example. (3 marks) 26. Describe the difference between transverse and longitudinal waves. (3 marks) 27. What is Snell's law? Calculate the angle of refraction for light passing from air (n=1) into water (n=1.33) with an incident angle of 30. (4 marks) 28. Explain the concept of diffraction and its applications. (3 marks) 29. Describe the properties of laser light. (3 marks) 30. What is the focal length of a convex lens with a radius of curvature of 20 cm? (Use the lens maker's formula) (3 marks)