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7 0

3 years ago

The half life for the decay of carbon-14 is 5.73 x 10 years. Suppose the activity due to the radioactive decay of the carbon-14

Elena-2011 [213]

Answer:

Age of the atifact is $4.2\times 10^{2}$ years

Explanation:

For first -order radioactive decay- $A_{t}=A_{0}(\frac{1}{2})^{\frac{t}{t_{\frac{1}{2}}}}$
$A_{t}$ represents activity of radioactive nuclide after t time, $A_{0}$ represents initial activity of radioactive nuclide and $t_{\frac{1}{2}}$ represents half-life
Here, $A_{t}=19Bq$ , $A_{0}=20Bq$ and $t_{\frac{1}{2}}=5.73\times 10^{3}years$

Plug-in all the given values in the above equation-

$19=20\times (\frac{1}{2})^{\frac{t}{5.73\times 10^{3}}}$

or, $t=4.2\times 10^{2}$

So, age of the atifact is $4.2\times 10^{2}$ years

6 0

3 years ago

A strontium-90 atom that has a lost two electrons has __________ protons, __________ neutrons, and __________ electrons.

MAXImum [283]

Answer:
A strontium-90 atom that has a lost two electrons has 38 protons, 52 neutrons, and 36 electrons.

Explanation:
Atomic number of Strontium (Sr) is 38.
Atomic number = number of protons
Hence, Strontium has 38 protons.

If the element is in neutral state,
number of protons = number of electrons.
Then, neutral Strontium atom should have 38 electrons.
But the question says Sr has lost 2 electrons. Hence, number of electrons should be 38 - 2 = 36.

Mass number = number of protons + number of neutrons.

The given mass number is 90. Hence, number of neutrons should be 90 - 38 = 52.

4 0

3 years ago