5.5.2 test (cst): computer-scored unit test
question 3 of 25
2 points
a sample contains 100 g of a radioactive isotope. how much radioactive
isotope will remain in the sample after 3 half-lives?
0
0
o a. 50g
o b. 259
c. 12.59
od. 1009
0

12. 5 g

Explanation:

Halflife is the time in which the radioactive substance becomes half of its initial value.

After one half life, the amount remains is one half

After 2 half lives, the amount remains is half of one half = 1 / 4 of initial value

After 3 half lives, the amount remains is 1/2 of 1/4 = 1/ 8 of initial amount

= 1 / 8 x 100 = 12. 5 g

luster is not a good characteristic to use by itself because luster is the property of minerals that indicates how much the surface of a mineral reflects light. the luster of a mineral is affected by the brilliance of the light used to observe the mineral surface.