A #1/4# inch thick lead sheet is used for protection from medical x-rays. If a single lead atom has a diameter #350# pm, how many atoms thick is the lead sheet?

1 Answer
anor277
Jan 14, 2016

#1/4# #"inch"# #=# #6.35# #xx# #10^-3# #m#.

#1# #"pm"# #=# #1# #xx# #10^-12# #m#

Explanation:

We assume that the lead atoms are close packed. Therefore we divide the sheet thickness by the diameter of of a single lead atom.

#(6.35xx10^-3cancelm)/(350xx10^-12cancelm)# #=# Something large. The difficulty with doing these problems is getting such a large number that intuitively you have no idea how feasible the number is.

PS can you help this gentleman, who has asked a similar question?. There are #454# #g# in #1# #"pound"#.

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