The Environmental Protection Agency has ben concerned about the levels of radon gas in homes. If a sample of gas taken from a basement contains 4.38 g of radon 222, how much radon will remain in the sample after 4 half-lives? 0.28 g

2.19 g

1.10 g

4.38 g

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.