Linear Density, Planar Density, Atomic Packing Factor {Texas A&M: Intro to Materials (MSEN 201)} 

J.S.S same doubt

Yeh,same doubt

Same doubt for me

@@francescobandozzi7708 same 🤣

well, after 6 years, No . Because you are considering your density along line, so ask yourself how it is shared along a line ? Not by volume.

Miah We only count that fraction of atoms within the line/area/volume of interest. So if we take planar density, the question is "how many atoms are there per unit area?" where the area is a square. if an atom is sitting exactly on the edge of a square, half of that atom is in one square region, the other half is in the neighboring region. Similarly, if the atom is sitting exactly on the corner of a square, it's evenly split between the for squares touching at that corner. This is the only way to make sure that the planar density is independent of where the square is located (picture shifting that square a little to the left or the right). Try this with a simple square lattice, and hopefully it should make a bit more sense!

1 1 1 triangle sides will be equal to each other. so 60 degress for each angle. 60 is 1/6 part of 360

i think you mean 1/8 of an atom at the corners. and the # of radii is the # of atoms. if you pass a vector through one radius of an atom, then the vector passed through one half of that atom. if you pass a vector through two radii of an atom, then the vector passed through that entire atom.