A
laser has a power output of 4.6 W and
a beam diameter of 2.6 mm. The
beam is aimed vertically upward on a perfectly reflecting cylinder.
We have to find the height of the cylinder so
that it is made to ‘hover’ by the radiation pressure
exerted by the beam. We
may assume that the density of the cylinder is
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Solution: Click For PDF Version The intensity of the laser beam of power output 4.6 W and a beam diameter of 2.6 mm will be
The force exerted by a laser beam of intensity I when it falls normally on a perfectly reflecting object of cross-sectional area A will be
The height H
of a perfectly reflecting cylinder of density
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