May someone help me solve this problem? Thank you Your firm has been hired to de
ID: 251521 • Letter: M
Question
May someone help me solve this problem? Thank you
Your firm has been hired to design a system that allows airplane pilots to make instrument landings in rain or fog. You've decided to place two radio transmitters 48 m apart on either side of the runway. These two transmitters will broadcast the same frequency, but out of phase with each other. This will cause a nodal line to extend straight off the end of the runway (see Figure 21.30b). As long as the airplane's receiver is silent, the pilot knows she's directly in line with the runway. If she drifts to one side or the other, the radio will pick up a signal and sound a warning beep. To have sufficient accuracy, the first intensity maxima need to be 64 m on either side of the nodal line at a distance of 4.4 km. What frequency should you specify for the transmitters? Express your answer using two significant figures.Explanation / Answer
I know that there will need to be completely destructive waves. And for that, L/=0.5, 1.5, 2.5.... But in order for her to be directly in line with the runway, L=0, so this would not be true. Also, I think this, L/=0.5, 1.5, 2.5, is only true when =0, 2, 4, etc.,
because the difference of path will cancel the difference if phase of the emitter, giving constructive interference.
At the bisection, L is still equal to 0, obviously. The point is that the condition for constructive vs destructive is switched compared to the case of emitters in phase. So the points where L/=0,1,2... correspond to destructive interference now (as opposed to the more usual case