Answer:
Wavelength,

Step-by-step explanation:
It is given that,
Two point sources (pixels) of monochromatic radiation can be resolved as close as 0.3 cm apart, x = 0.3 cm = 0.003 m
Diameter of lens, d = 7 cm = 0.07 m
Distance from the view line, D = 1500 m
We need to find the wavelength of the radiation. The formula for resolving power of Rayleigh criterion is given by :




So, the wavelength of the radiation is
. Hence, this is the required solution.