Which of the following is the best description of thermal conducton A. particles following a temperature difference toward the heat source
B. Particles bumping into each other and there heat transfer due to direct contact
C. particles flowing in circular currents
D. particles flowing to the warmest region of an object

Two loudspeakers, 5.5 m apart and facing each other, play identical sounds of the same frequency. you stand halfway between them, where there is a maximum of sound intensity. moving from this point toward one of the speakers, you encounter a minimum of sound intensity when you have moved 0.33 m . assume the speed of sound is 340 m/s.part a) what is the frequency of the sound? part b) if the frequency is then increased while you remain 0.21 m from the center, what is the first frequency for which that location will be a maximum of sound intensity? express your answer to two significant figures and include the appropriate units.