posted by hiloo .
Microwaves (520cm wavelength) enter a long narrow window of a building (which is opaque to microwaves except or the window). If the window is 36 cm wide, what is the distance from the central maximum to the first order minimum of a diffraction patter produced by the window on a wall 6.50 m away?
This question can be solved by the diffraction equation. sinTheta= wavelength/slitwidth. Then use the Theta to calcualte the distance from the geometry.
An interesting variation of this occurred in the 1980's, spys being spys, microwaves were used to listen through windows and sometimes walls to humans speaking. Thus, building vulnerable to sensitive to snooping had microwave shields (screens) installed in the windows and walls.