The packing efficiency of the two dimensional square unit cell shown below is:

Options

A. `39.27%`
B. `68.02%`
C. `74.05%`
D. `78.54%`

Answer

D

Explanation

`sqrt(2)L =4r rArr (r )/(L) =(sqrt(2))/(4)`
Packing efficiency `=(2pi r^(2))/(L^(2)) = 2 xx ((1)/(2sqrt(2)))^(2)=(pi)/(4) =78.5%`.