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 ..
