A double-slit arrangement is used to determine the wavelength of microwaves. The apparatus is set up as shown in the diagram below:
The two slits act as coherent sources with a slit separation of s=0.20 ms = 0.20\text{ m}s=0.20 m. The perpendicular distance from the slits to the line AB AB\,AB is D=0.50 mD = 0.50\text{ m}D=0.50 m. The receiver R R\,R is initially at the midpoint of ABABAB, which is equidistant from both slits. R R\,R can be moved up to 0.25 m towards either A A\,A or B B\,B along the line ABABAB.
Suggest why Young's double-slit equation should not be used to calculate the wavelength in this experiment.
The actual wavelength of the microwaves is known to be approximately 1.5 cm. Deduce whether this experimental setup is suitable for determining the wavelength. Support your answer with a path difference calculation.