Half life is the time taken by a radioactive isotope to decay by half its original mass.
The original mass is 200 g
Time taken is 60 hours
Final mass is 25 g
Therefore;
Final mass = Original mass × (1/2)^n; where n is the number of half lives.
25 = 200 (1/2)^n
1/8 = (1/2)^n
n = 3
Three half lives = 60 hours
1 half lives = 20 hours
Therefore; the half life of the radioactive nucleus is 20 hours
The wavelengths of light that an atom gives off when an electron falls to a lower energy level corresponds to Emission spectrum , Option D is the correct answer.
<h3>What is Emission Spectrum ?</h3>
Light is absorbed or emitted when an electron jumps or falls into an energy level.
The energy of light absorbed or emitted is equal to the difference between the energy of the orbits.
Therefore , the wavelengths of light that an atom gives off when an electron falls to a lower energy level corresponds to Emission spectrum.
To know more about Emission Spectrum
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Answer:
its atomic number will be 3 and it's mass number will be 7. it is lithium
Answer:
<h2>Density = 0.5 g/mL</h2>
Explanation:
The density of a substance can be found by using the formula
<h3>
</h3>
From the question
mass = 60 g
volume = 120 mL
Substitute the values into the above formula and solve
That's
<h3>
</h3>
We have the final answer as
<h3>Density = 0.5 g/mL</h3>
Hope this helps you
