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bang911
Aug23-04, 09:34 PM
I just had my first college physics class today, and already I'm stuck on the first problem. I already had physics in HS and I expected I wouldn't have that much trouble in college. So here is a question that I have no clue how to answer.

A crystalline solid consists of atoms stacked up in a repeating lattice structure. Consider a crystal as shown in figure p1. The atoms reside at the corners of the cubes of side L = 0.200 nm. One piece of evidence for the regular arrangement of atoms comes from the flat surfaces along which a crystal separates, or cleaves, when it is broken. Suppose this crystal cleaves along a face diagonal as in p2. Calculate the spacing d between two adjacent atomic planes that separate when the crystal cleaves.

(the pictures are in 3d)

OOOOOOOO
OOOOOOOO
OOOOOOOO
l<-L->l \d\



OO OOOOOO
OOO OOOOO
OOOO OOOO



the answer is .141 nm

so if anyone would help me out with this i would greatly appreciate it
ehild
Aug25-04, 01:21 AM
A crystalline solid consists of atoms stacked up in a repeating lattice structure. Consider a crystal as shown in figure p1. The atoms reside at the corners of the cubes of side L = 0.200 nm. One piece of evidence for the regular arrangement of atoms comes from the flat surfaces along which a crystal separates, or cleaves, when it is broken. Suppose this crystal cleaves along a face diagonal as in p2. Calculate the spacing d between two adjacent atomic planes that separate when the crystal cleaves.

(the pictures are in 3d)



Well, maybe my picture helps.

ehild
JasonRox
Aug25-04, 10:09 AM
Yeah, that picture is helpful.
da_willem
Aug25-04, 11:04 AM
Just use the Pythagorean theorem :cool:
bang911
Aug25-04, 10:11 PM
Ya I had no clue how the pythagorean theorm was to be used when i read the problem. Thanks for the post and that nice diagram though. Doesn't seem tough any more. :cool:
ehild
Aug26-04, 12:25 AM
Ya I had no clue how the pythagorean theorm was to be used when i read the problem. Thanks for the post and that nice diagram though. Doesn't seem tough any more. :cool:

It's a pleasure ... :smile:

ehild