The optician's prescription for a spectacle lens is marked + 0.5 D. What is the : (a) nature of spectacle lens ? (b) focal length of spectacle lens ?

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Solution

a)-The optician's prescription for a spectacle lens is marked + 0.5 D.
power is positive so lens is converging.

b) $F = \frac{1}{P}$

$= \frac{1}{0.5} = 2 m$

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The optician's prescription for a spectacle lens is marked + 0.5 D. What is the : (a) nature of spectacle lens ? (b) focal length of spectacle lens ?

a)-The optician's prescription for a spectacle lens is marked + 0.5 D. power is positive so lens is converging. b)F=1P =10.5=2 m

a)-The optician's prescription for a spectacle lens is marked + 0.5 D.
power is positive so lens is converging.

b) $F = \frac{1}{P}$

$= \frac{1}{0.5} = 2 m$