A narrow beam of sound from a loudspeaker strikes a large
MATHEMATICS · Multi-part · GCSE · Mathematics · Geometry and Measures · Geometry and Measures
Problem
A narrow beam of sound from a loudspeaker strikes a large, smooth vertical wall. The beam makes an angle of 25∘ with the normal to the wall at the point of incidence. The centre of the loudspeaker is 6.0m away from the wall along the direction of the incident beam.
(i) Draw a labelled ray diagram to show the incident and reflected beams and mark all relevant angles.
(ii) Calculate the angle between the incident beam and the reflected beam.
(iii) Find the total distance travelled by the sound in going from the loudspeaker to the wall and back to the loudspeaker.
(iv) If the speed of sound in air is 340m/s, calculate the time interval between the emission of the sound pulse and the reception of its reflection at the loudspeaker.