Two radio antennas are 100 m apart along a north-south line. They broadcast identical radio waves at a frequency of 3.0 MHz. Your job is to monitor the signal strength with a handheld receiver. To get to your first measuring point, you walk 800 m east from the midpoint between the antennas, then 600 m north.

a. What is the phase difference between the waves at this point?

b. Is the interference at this point maximum constructive, perfect destructive, or somewhere in between? Explain.

c. If you now begin to walk farther north, does the signal strength increase, decrease, or stay the same? Explain.