Answer:
Distance will be 49.34 m
Explanation:
We have given wavelength ![\lambda =1.4cm =0.014m](https://tex.z-dn.net/?f=%5Clambda%20%3D1.4cm%20%3D0.014m)
Diameter of the antenna d = 2.7 m
Range L = 7.8 km = 7800 m
We have to find the smallest distance hat two speedboats can be from each other and still be resolved as two separate objects D
We know that distance is given by ![D=\frac{L1.22\lambda }{d}=\frac{7800\times 1.22\times 0.014}{2.7}=49.3422m](https://tex.z-dn.net/?f=D%3D%5Cfrac%7BL1.22%5Clambda%20%7D%7Bd%7D%3D%5Cfrac%7B7800%5Ctimes%201.22%5Ctimes%200.014%7D%7B2.7%7D%3D49.3422m)
So distance D will be 49.34 m
Period of months where the weather is the coldest and the days are the shortest.