Question

The half-life of a certain material is 0.004 second. Approximately how much of a 20-gram sample will be left after 0.016 second?

Answer 1

Answer:

D. 1.25 grams

Step-by-step explanation:

Half-life is: 0.004 sec

Time spent : 0.016 sec

Quantity = 20 gram

In order to find the material after 0.016 sec, we have to calculate how many number of half-lives have been passed

No. of half-lives passed = 0.016/0.004

= 4

The number of lives passed will be raised to the power of 0.5.

0.5 ^ 4 = 0.0625

The answer will be multiplied with the quantity we started with.

Remaining material is:

20*0.0625 = 1.25 grams

Hence, Option D is correct ..