A narrow beam of sound travels in air and strikes a large flat wooden wall.
(i) The beam makes an angle of 25∘ with the wall when it arrives. Draw a neat ray diagram and determine the angle of reflection.
(ii) Calculate the angle between the incident and the reflected rays.
(iii) The beam is now rotated by 15∘ towards the normal to the wall, while the wall itself remains fixed. Find the new angle between the incident and reflected rays.