Useful Approximate Numbers
•
distance between atoms ~3
Å
~ 10
–
7.5
cm
(3
x
10
–
8
cm ~ 10
0.5
x
10
–
8
cm = 10
–
7.5
cm)
•
# atoms/cm ~ 10
7.5
•
# atoms/cm
2
~ (10
7.5
)
2
= 10
15
•
# atoms/cm
3
~ (10
7.5
)
3
= 10
22.5