Question

the power of a lens if -0.2 . what will be the nature and length of the lens

Answer 1

Answer:

minus indicator that the image is formed by a concave mirror and the image so formed is virtual, erect and diminished and the focal length is P=1/F

0.2=1/F

0.2F=1

2F=10

hence, F=5

Answer 2

$\Large\underline{\underline{\sf \green{Given}:}}$

• Power of lens (P) = - 0.2 D

$\Large\underline{\underline{\sf \green{To\:Find}:}}$

• Nature of lens = ?

• Focal Lenght of lens = ?

$\Large\underline{\underline{\sf \green{Formula\: Used}:}}$

$\large{\boxed{\sf \red{Power (P)=\dfrac{1}{Focal\: Lenght}}}}$

$\Large\underline{\underline{\sf \green{Solution}:}}$

$\implies{\sf -0.2=\dfrac{1}{f}}$

$\implies{\sf f=- \dfrac{1}{0.2} }$

$\implies{\sf f=-50\:cm}$

And ,

Nature of lens is Convex Lens .

$\Large\underline{\underline{\mathfrak \red {Remember}:}}$

Power of Convex lens is Positive

and , Power of Concave lens is Negative .