Find the diameter of the image of the moon formed by a spherical concave mirror of focal length 7.6 m. The diameter of the moon is 3450 km and the distance between the earth and the moon is 3.8 xx 10^5 km

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loans911z2s · Accepted Answer

u  =  −  3.8  ×      10    5       k  m Diameter of moon = 3450 km   f  =  −  7.6     m    ⇒      1    v    =      1    u    +      1    f      ∴      1    v    +  (  −      1          3.8      ×              10        5              )  =  (      1    57.6    ) Given that the moon is much farther away from Earth than the focal length, it can be assumed that   ∞   ⇒ At the focus, an inverted image will be created.   ⇒      1    v    =  −      1    7.6      ⇒  v  =  −  7.6     m    m  =  −      v    u    =            d              i        m        a        g        e                    d              o        b        j        e        c        t                ⇒            −      (      −      7.6      )              (      −      3.8      ×              10        8            )        =            d              i        m        a        g        e                    3450      ×              10        3                    d          i      m      a      g      e        =            3450      ×      7.6      ×              10        3                    3.8      ×              10        8                =  0.069  m  =  6.9     c  m

Find the diameter of the image of the moon formed by a spherical concave mirror of focal length 7.6 m. The diameter of the moon is 3450 km and the distance between the earth and the moon is 3.8 xx 10^5 km

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