Answer: 28.71 km
Explanation:
For the convex mirror (ocean):
Radius of curvature = 6.4*10^3 km
Focal length (f) = R/2 = 3.2*10^3 km
Object distance (u) = -3.84*10^5
Mirror formula: [tex]\frac{1}{u} + \frac{1}{v} = \frac{1}{f}[/tex]
[tex]\frac{1}{u} + \frac{1}{v} = \frac{1}{f}[/tex]
[tex]\frac{-1}{3.84*10^5} + \frac{1}{v} = \frac{1}{3.2*10^3}[/tex]
v = 3173.55km
Magnification, [tex]m = \frac{-v}{u} = \frac{-3173.55}{-3.84*10^5} = \frac{h_{i} }{h_{o} }[/tex]
So, height of image/height of object = 3173.55/3.84*10^5
Diameter of image = 3173.55/3.84*10^5 * 3475
Diameter of image = 28.71 km
Therefore, the diameter of the image is 28.71 km