If the image formed by a lens for all positions of an object placed in front of it is always erect and diminished, what is the nature of this lens? Draw a ray diagram to justify your answer. If the numerical value of the power of this lens is 10 D, what is its focal length in the Cartesian system?
CBSE OUTSIDE DELHI - SET 1 2017
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Concave/ diverging lens.
Direction of rays$\text{f}=\frac{1}{\text{P}}$
$\text{P}=-10\text{D},$
$\text{f}=\frac{1}{-10\text{D}}=-0.1\text{m}/-10|\text{cm}$
Direction of rays$\text{f}=\frac{1}{\text{P}}$
$\text{P}=-10\text{D},$
$\text{f}=\frac{1}{-10\text{D}}=-0.1\text{m}/-10|\text{cm}$
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