Question

For a person with a Near Point (NP) = 45 cm, what would be his prescription's lens power = _________ diopters A) 1.08 diopters B) 2.842105 diopters C) 1.778 diopters D) 0.54 diopters E) 0.225 diopters

Answer 1

Answer:

The power of lens is 2.22 D.

Explanation:

Given that,

Distance of image v= 45 cm

We know that,

Distance of object u= ∞

Power of lens is the reciprocal of focal length.

$P=\dfrac{1}{f}$

We need to calculate the power of lens

Using formula of lens

$\dfrac{1}{f}=\dfrac{1}{v}+\dfrac{1}{u}$

Where, f = focal length

v = image distance

u = object distance

Put the value into the formula

$\dfrac{1}{f}=\dfrac{1}{45}+\dfrac{1}{\infty}$

$\dfrac{1}{f}=\dfrac{1}{0.45}+0$

$P=\dfrac{1}{f}=2.22$

Hence, The power of lens is 2.22 D.