A simple microscope is rated at 5 X for a normal relaxed eye. Determine its magnifying power for a relaxed farsighted eye that has a near point of 40 cm .

Step-by-step solution

The magnifying power of a simple microscope for a relaxed eye (image at infinity) is given by M = D f , where D is the near point of the observer's eye and f is the focal length of the lens. For a normal eye, the near point is D = 25 cm . Given that the magnifying power is 5 X , we have: 5 = 25 f f = 5 cm For a farsighted eye with a near point D' = 40 cm , the magnifying power for a relaxed eye will be: M' = D' f = 40 5 = 8 Thus, the magnifying power is 8 X .