Question

A myopic person has a far point of 1.000m. If she wears her eyeglass 2.0cm in fromt of here eyes, what is the power of her eye glass?

Answer 1

51 dioptre

Step-by-step explanation:

u = Object distance = 2 cm

v = Image distance = 1 m

f = Focal length

Lens Equation

`(1)/(f)=(1)/(u)+(1)/(v)\\\Rightarrow (1)/(f)=(1)/(0.02)+(1)/(1)\\\Rightarrow (1)/(f)=(1.02)/(0.02)\\\Rightarrow (1)/(f)=51\\\Rightarrow f=(1)/(51)`

Power of lens

`P=(1)/(f)\\\Rightarrow P=(1)/((1)/(51))\\\Rightarrow P=51\ D`

Power of the eye lens is 51 dioptre.