Find the power of lens to be used if the far point of an eye has changed from infinity to 5m(plz explain using u and v)

Dear Student ,
Here in this case from th given data ,
$$\begin{gathered} u=\infty , v=5 m \\ So , \frac{1}{v}-\frac{1}{u}=\frac{1}{f} \\ \Rightarrow \frac{1}{5}-\frac{1}{\infty }=\frac{1}{f} \\ \Rightarrow \frac{1}{f}=\frac{1}{5} \end{gathered}$$
If the far point of an eye lens has changed from infinity to 5 m then the focal length will be 5 m .
So the power of the lens is , P = 1/f = 1 /5 = 0.2 D
Regards