To calculate how many photons are in a certain amount of energy (joules) we need to know how much energy is in one photon.
Start by using two equations:
Energy of a photon = Frequency * Planck's constant (6.626 * 10^(-34) J-s)
Speed of light (constant 3 * 10^8 m/s) = Frequency * Wavelength
Which means:
frequency = Speed of Light / Wavelength
So energy of a photon = (Speed of light * Planck's constant)/(Wavelength)
You may have seen this equation as E = hc/<span>λ</span>
We have a wavelength of 691 nm or 691 * 10^-9 meters
So we can plug in all of our knowns:
E = (6.626 * 10^(-34) J-s) * (3.00 * 10^8 m/s) / (691 * 10^-9 m) =
2.88 * 10^(-19) joules per photon
Now we have joules per photon, and the total number of joules (0.862 joules)
,so divide joules by joules per photon, and we have the number of photons:
0.862 J/ (2.88 * 10^(-19) J/photon) = 3.00 * 10^18 photons.
Answer:
Single Displacement reaction
In a displacement reaction, a more reactive element replaces a less reactive element from a compound.
Change in colour takes place with no precipitate forms.
Metals react with the salt solution of another metal.
Examples:
2KI + Cl2 → 2KCl + I2
CuSO4 + Zn → ZnSO4 + Cu
Double displacement reaction
In a double displacement reaction, two atoms or a group of atoms switch places to form new compounds.
Precipitate is formed.
Salt solutions of two different metals react with each other.
Examples:
Na2SO4 + BaCl2 → BaSO4 + 2NaCl
2KBr + BaCl2 → 2KCl + BaBr2
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Answer:
Motile bacteria have flagella, while nonmotile bacteria do not.
Explanation:
Answer:
Nucleus
Explanation: it is the center of the atom, and contains protons and nuetrons
