Question

Someone plans to float a small, totally absorbing sphere 0.532 m above an isotropic point source of light, so that the upward radiation force from the light matches the downward gravitational force on the sphere. The sphere's density is 20.8 g/cm3, and its radius is 2.34 mm. (a) What power would be required of the light source? (b) Even if such a source were made, would the support of the sphere be unstable? Assume that the speed of light is 2.998*108 m/s.

Answer 1

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3 20.8 2 3

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