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 ______ .

Answer

`13.89`

Explanation

Here, angular resolution of human eye,
`phi = 5. 08 xx 1 ^(-4) ` rad
The linear distance between two successive dots in a typical photo printer is `1 = (2.54)/(360) cm`
At a distance of Z cm, the gap distance I will subtend an angle, `phi = (1)/(Z)`
`therefore Z = (1)/(phi)`
` = (2. 54 xx 10 ^(-2))/( 360 xx 5. 08 xx 10 ^(-4)) = 13. 89 cm `