The diameter of a nickel is 21 mm . How far from your eye must it...

The diameter of a nickel is 21 mm .

How far from your eye must it be held so that it has the same apparent size as the moon? (Use the astronomical data inside the back cover of the textbook.)

Expert Solution

given

Nickel diameter d= 21 mm = 21*10^-3 m

We know that two round or spherical objects have the same angular diameter, even though they are at different distances from the oswerver.

they have same angular size, that is d/l nickel = D/L moon

D diameter of moon = 3474*10^3 m, L distance from moon to earth = 3.84*10^8 m
d diameter of nickel = 21*10^-3 m, l=?

      D/L = d/l     ==>   l = d*L/D ,
              l= (21*10^-3*3.84*10^8)/3474*10^3
                                     l = 2.3212 m

nickel must be held so that it has the same apparent size as the moon is 2.3212 m from eye.

genius_generous answered 9 months ago

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