Set this up as
10 = 40 (1/2)t/28
and solve for t in years.
10/40 = (1/2)t/28
log(0.25) = (t/28) log(0.5)
t = 28 log(0.25) / log(0.5) years = 56 years
Test the answer:
56 years = 2(28 years) = 2 half-lives, so the remaining amount should be 1/2 of 1/2 of the initial amount, i.e. 1/4 of the initial amount, and 10 mg = 1/4 of 40 mg.
The waves crash into the sand, sometimes creating dunes, and it can also wash some sand out into the ocean. Hope this helps!
<u>Answer:</u>
Delta.
<u>Explanation:</u>
At the river mouth, a river loses energy and starts to deposit its sediments.
Hope this helps you :)
4) Polaris
Stars emit light with energy generated by nuclear fusion, think of the Sun as an example. Polaris is a star, it's the brightest star in the little bear constellation, and therefore the correct answer.