英语翻译A loudspeaker which emits sound of frequency 1000 Hz is

英语翻译A loudspeaker which emits sound of frequency 1000 Hz is placed several meters from a plane reflecting wall in a large chamber containing a gas.A microphone M,connected to a cathode ray oscilloscope ,detects a series of low and high intensity signals as it moves along the line joining the loudspeaker B and the wall.if the microphone detects a series of 10 low intensity signals while moving through a distance S of 2m,what is the speed of sound in the chamber?A 110m/s B220ms C 330 D 440