Question:

A loud speaker L is placed in long narrow hall with two

Last updated: 6/11/2023

A loud speaker L is placed in long narrow hall with two

A loud speaker L is placed in long narrow hall with two doors D and D open to the very long playground as shown in figure The distance D D is 12 m distance between two parallel walls of hall is 9 m The loud speaker is fitted to the wall on a line perpendicular to D D which passes through door D On same line one interference maxima is obtained at P at distance 9 m from door D It is known that loud speaker emits single frequency sound of frequency 150 Hz and because of presence of some other gas in hall and bit high temperature speed of sound waves in hall is 450 m s while in air in ground is 300 m s Hall 9m D Play ground P Q Close to P next interference maximum at Q is obtained if PQ 7 m Just in front of door D an interference minimum will be obtained On line joining L D 2 P and Q maximum six interference minima will be obtained