Some telephoto cameras use a mirror rather than a lens. what radius of curvature mirror is needed to replace a 800 mm-focal length telephoto lens?

 R= 1.6 m

Explanation:

The radius of curvature of mirror and focal length is given by

                   R=2f

           where R is the radius of curvature

                      f is the focal length

As the telephoto camera uses mirror instead of lens , we can calculate the radius of curvature of mirror which has focal length of 0.8m which is same as that of lens.

          The radius of curvature of mirror is R =2*0.8

                         R= 1.6 m

another example of kinetic energy would be,

kinetic energy   >     moving energy

answer   >   letter choice (c),   a hammer falling off a table.

hope that !                                         : )

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