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Effectus [21]
3 years ago
10

Tooth fillings are often made of gold or porcelain because these materials are ______.

Physics
2 answers:
garri49 [273]3 years ago
4 0
Tooth fillings are often made of gold or porcelain because these materials are nonreactive.

b. nonreactive.
damaskus [11]3 years ago
3 0

Tooth fillings are often made of gold or porcelain because these materials are:

b. nonreactive

That means that they don't corrode or rust and they are resistible to staining.Their thermal conductibility is low.

Explanation:

Porcelain-fused-to-metal crowns. PFM crowns are an approximately esthetic improvement that has been in use for more than 40 years. In one way, they blend the best of both worlds, a crown made of “refined or noble” metal (gold or platinum), which is strong, fits correctly and is bonded/bonded to the tooth.

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A. 2.82 eV

B. 439nm

C. 59.5 angstroms

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E_{5,2}=-13.6(\frac{1}{5^2}-\frac{1}{2^2})=2.82eV

B. The energy of the emitted photon is given by the following formula:

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You first convert the energy from eV to J:

2.82eV*\frac{1J}{6.242*10^{18}eV}=4.517*10^{-19}J

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C. The radius of the orbit is given by:

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You use the equation (3) with n=5:

r_5=5^2(2.380)=59.5

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