[SOLVED] Interference of waves - 2 point source Question 1. The problem statement, all variables and given/known data Two towers of a radio station are 400 m apart along an east-west line. The towers act essentially as point sources, radiating in phase at a frequency of 1.00 x 10^6 Hz. a) In what directions is the intensity of the radio signal at a maximum for listeners 20 km north of the transmitter (but not necessarily directly north of it)? b) In which directions would you find the intensity at a minimum, north of the transmitter, if the towers were to start transmitting in opposite phase? 2. Relevant equations (n-1/2)lamda = sin theta d where n - the number of nodes theta - the angle between nodes d - distance between 2 point sources velocity= lamda x frequency 3. The attempt at a solution I thought that I want to figure out the angle between the central max, and the first node - where the radio signal would be at a minimum (due to destructive interference) and then divide it by 2 to get the angle at the maximum (constructive interference). lamda= 3.00 x 10^8 m/s = 300 m 1.00 x 10 ^ 6 Hz ( 300m) (1-1/2)= sin theta 400 m theta = 22 degrees / 2 = 11 degrees My answer was N 11 E or N 11 W, whereas the real answer should be N 49 E or N 49 W. Help please! Thanks!