KVPY 2019 SB SX Exam Previous Papers

Two identical coherent sound sources R and S with frequency f are 5 m apart. An observer standing equidistant from the sources and at a perpendicular distance of 12 m from the line RS hears maximum sound intensity. When he moves parallel to RS the sound intensity varies and is a minimum when he comes directly in front of one of the two sources. Then a possible value of f is close to (the speed of sound is 330 m/s)