Question

. The half-life of a radioactive substance is four days.
(a) Find the decay constant.
(b) How much of an initial 2-g sample will remain after 10 days?

Answer 1

What do you think? Also, is that all of your question?

Answer 2

yes this is all of the question and i don't even understand what it's asking

Answer 3

Me either. sorry man

Answer 4

it's ok..my professor never never teaches what he tests us on

Answer 5

ikr, maybe @KendrickLamar2014 or @ShadowLegendX can help you.

Answer 6

I'm not sure about this .-.

Answer 7

ok thanks guys

Answer 8

Here's a good explanation of half life
http://www.1728.org/halflife.htm and here's a solution:

half life = 4 days
How much of 2 gram sample is left after 10 days?
Ending Amount = Beginning Amount / (2^n)
where n = number of half-lives

if half life = 4 days, after 10 days, 2.5 half lives have passed.

Ending Amount = 2 grams / (2^2.5)
Ending Amount = 2 grams / 5.657
Ending Amount = 0.3535 grams

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The decay constant (represented by the Greek letter lambda, which you don't need now) equals (natural log of 2) / half-life

decay constant = 0.6931471806 / 4

More about the decay constant here:
https://en.wikipedia.org/wiki/Half-life