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adelina 88 [10]
3 years ago
5

Maggie was doing research for her Ph.D. in physics when a 12 mg sample of radioactive material decayed to 3 mg in 26 minutes. De

termine the half life of this substance.
Mathematics
1 answer:
netineya [11]3 years ago
3 0

The general way to work this out is to solve the general expression for
the remaining quantity versus half-life, using logarithms.  But that's not
necessary with these numbers.

Look at the numbers:

-- 3 mg is  1/4  of  12 mg.

-- 1/4  is the product of  (1/2) x (1/2).

-- So the  3 mg is what's left of  12 mg after  2  half-lives.
The  26  minutes must be two half-lives.

-- The half-life of that substance is  26/2 = <em>13 minutes</em>.

Go Maggie !

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Answer:

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Step-by-step explanation:

Given

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Required

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f(x) = \left \{ {{1\ 9 \le x \le v^\frac{1}{3} - 9} \atop {0\ elsewhere}} \right.

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So:

f(v) = \left \{ {{\frac{1}{3}v^{-\frac{2}{3}}\ 9^3 \le v \le 10^3} \atop {0, elsewhere}} \right.

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