Find the diameter of the image of the moon formed by a spherical concave mirror of focal length 11.4m.The diameter of the moon is 3450km and the distance between the earth and the moon is 3.8*10^5 km.?

f=11.4,u=3.8*10^5 km so u>>f ....then v=f=11.4. m=-v/u =11.4m/3.8*10^8 m =-3*10^-8. now| m|=hi/ho ,,,3*10^-8 =hi/3.45*10^6,,,,,,hi=10.35*10^-2,,,,,hi=10.35mm I think,it clear your doubt