- Frequency=v=2×10^15Hz
- Energy=E
Using planks quantum theory




From the information given:
- The volume of the graduated cylinder = 50.0 mL
- when a sterling silver pendant is added, the volume increases to = 61.3 mL
∴
The volume of the sterling silver pendant is:
= 61.3 mL - 50.0 mL
= 11.3 mL
Since, 1 mL = 1cm³
Then;
11.3 mL = 11.3 cm³
- the density of the sterling silver = 10.25 g/cm³
Using the relation for Density; i.e.


mass = 10.25 g/cm³× 11.3 cm³
mass of the sterling silver = 115.825 grams
Recall that sterling silver has:
- 92.5% silver and;
- 7.5% copper
∴
The mass of the copper contained in the sterling silver pendant can be calculated as:

= 8.687 grams
Therefore, we can conclude that the mass of the copper contained in the sterling silver pendant is 8.687 grams
Learn more about the relation between Density, Mass, and Volume here:
brainly.com/question/24386693?referrer=searchResults
Answer: D) helium.
Explanation:
Nuclear fission is a process which involves the conversion of a heavier nuclei into two or more small and stable nuclei along with the release of energy.

Nuclear fusion is a process which involves the conversion of two small nuclei to form a heavy nuclei along with release of energy.
Example: 
Thus when deuterium and tritium , the two isotopes of hydrogen are fused, a heavier nuclei helium is being formed from two smaller nuclei releasing a neutron.
Answer:
C. Xenon
Explanation:
The question only requires you to use your visual skills to identify the unknown gas. Look at the spectra of unknown gas and xenon, are they not identical? SInce they are same, the unknown sample must be xenon.
Answer:
the number of neutrons in above isotope = A - Z = 27 - 13 = 14. Note: The molar mass of aluminium, which is average of atomic masses of all isotopes = 26.981538 g/mol, since 13Al27 is the major isotope.
Explanation: