The human eye has an approximate angular resolution of `phi = 5.8xx10^(-4)` rad and a typical photo printer prints a minimum of 300 dpi (dots per inch, `= 2.54 cm`). Aminimum distance 'z' should a printed page be held so that one doesnot see the indivdual dots is ______ .

Explanation

Given, angular resolution of human eye, `phi= 5.8xx10^(-4)` rad.
and printer prints 300 dot per inch.
The linear distance between two dots is `l=(2.54)/(300) cm=0.84xx10^(-2)` cm.
At a distance of zcm, this subtends an angle , `phi=(l)/(z)`
`:. z=(l)/(phi)=(0.84xx10^(-2) cm)/(5.8xx10^(-4))=14.5 cm`