$A$ person has a near point of $50 \, cm$ and a far point of $3 \, m$. What power of lens is required to $(i)$ read and $(ii)$ see distant stars?

Your friend is having an eyesight problem. She is not able to see a distant uniform window mesh clearly,and it appears to her as non-uniform and distorted. The doctor diagnosed the problem as:

$A$ person wears normal spectacles in which the distance between the glasses and the eyes is approximately $2 \, cm$. The power required is $-5 \, D$. If he wears contact lenses,then the required power is ......... $D$.

$A$ student studying the similarities and differences between a camera and the human eye makes the following observations:
$I$. Both the eye and the camera have convex lenses.
$II$. In order to focus,the eye lens expands or contracts while the camera lens moves forward or backward.
$III$. The camera lens produces upside down real images while the eye lens produces only upright real images.
$IV$. $A$ screen in a camera is equivalent to the retina in the eyes.
$V$. $A$ camera adjusts the amount of light entering in it by adjusting the aperture of the lens. In the eye,the cornea controls the amount of light. Which of the above statements are correct?

Match the List-$I$ with the List-$II$ from the combinations shown:

$(I)$ Presbyopia	$(A)$ Sphero-cylindrical lens
$(II)$ Hypermetropia	$(B)$ Convex lens of proper power may be used close to the eye
$(III)$ Astigmatism	$(C)$ Concave lens of suitable focal length
$(IV)$ Myopia	$(D)$ Bifocal lens of suitable focal length

The near point and far point of a normal human eye are respectively: