1. The problem statement, all variables and given/known data An aircraft causes a horizontal layer of charged particles to be formed in the atmosphere. Radio waves are relected without phase from this layer. Radio waves of frequency 8.00 x 10^2 kHz are received at a location 12 km from the transmitter. What is the minimum height of the layer of particles if radio reception fades due to destructive interference between the direct beam and the reflected beam? 2. Relevant equations lamba = v/f 3. The attempt at a solution I have found a wavelength of 375 m. Now i'm not sure what to do from here. The answer is supposed to be between 1 and 2. Can someone help me get past this road block?