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

the answer is a)

mark brainliest

can be answered using momentum.

momentum = p

p1= mass1 * velocity1

p1 = p2

therefore

p1 = 6kg * 4m/s

p1 = 24kgm/s

p2=m2 * v2

24 kgm/s = 7kg * v2

v2 = 24 kgm/s / 7kg

v2= 3.42 m/s