<u>Conversion Factors:</u>
1.61 km = 1 mile
60 sec = 1 min
60 min = 1 hour
<u />
Use dimensional analysis to solve.
×
×
×
× 

= 36 miles/hour
If done properly, you should be left with the units <em>miles/hour</em>
<em />
Time passed Time passed 14C initially present 14C at end of half-life
(half life) (Years)
........................................................................................................................
0 0 1,000,000 1,000,000
1 5750 ..... 5,00,000
2 11500 ..... 2,50,000
3 17250 ..... 1,25,000
4 23000 ..... 62,500
Since, wood sample contained 1/16 of current atmospheric concentration of 14C. It means that sample has crossed 4 half-life. Number atoms left are 4 half life = 62,500