Answer:
a) E₀ = 2.125 eV, b) # photon2 = 9.2 10¹⁵ photons / mm²
Explanation:
a) To calculate the energy of a photon we use Planck's education
E = h f
And the ratio of the speed of light
c = λ f
We replace
E = h c /λ
Let's calculate
E₀ = 6.63 10⁻³⁴ 3 10⁸/585 10⁻⁹
E₀ = 3.40 10⁻¹⁹ J
Let's reduce
E₀ = 3.4 10⁻¹⁹ J (1 eV / 1.6 10⁻¹⁹ J)
E₀ = 2.125 eV
b) Let's look for the energy in each pulse
P = E / t
E = P t
E = 20.0 0.45 10⁻³
E = 9 10⁻³ J
let's use a ratio of proportions (rule of three) if we have the energy of a photon (E₀), to have the energy of 9 10⁻³ J
# photon = 9 10⁻³ /3.40 10⁻¹⁹
# photon = 2.65 10¹⁶ photons
Let's calculate the areas
Focus area
A₁ = π r²
A₁ = π (3.4/2)²
A₁ = 9,079 mm²2
Area requested for calculation r = 1 mm
A₂ = π 1²
A₂ = 3.1459 mm²
Let's use another rule of three. If we have 2.65 106 photons in an area A1 how many photons in an area A2
# photon2 = 2.65 10¹⁶ 3.1459 / 9.079
# photon2 = 9.2 10¹⁵ photons / mm²
The density of the substance is<u> 10.5 g/cm³.</u>
The jewelry is made out of <u>Silver.</u>
Density ρ is defined as the ratio of mass <em>m</em> of the substance to its volume V<em>. </em> The cylinder contains a volume <em>V₁ of water</em> and when the jewelry is immersed in it, the total volume of water and the jewelry is found to be V₂.
The volume <em>V</em> of the jewelry is given by,

Substitute 48.6 ml for <em>V₁ </em>and 61.2 ml for V₂.

calculate the density ρ of the jewelry using the expression,

Substitute 132.6 g for <em>m</em> and 12.6 ml for <em>V</em>.

Since
,
The density of the jewelry is <u> 10.5 g/cm³.</u>
From standard tables, it can be seen that the substance used to make the jewelry is <u>silver</u><em><u>, </u></em>which has a density 10.5 g/cm³.
Answer:
k = 5.05 N/m
Explanation:
In order to calculate the spring mass of the system, you use the following formula:
(1)
T: period of oscillation of the system
m: mass of the air-track glider = 200g = 0.200 kg
k: spring constant = ?
You first calculate the period of oscillation:

Next, you solve the equation (1) for k, and then you replace the values of the other parmateres:

The spring constant of the spring is 5.05 N/m
One of the major limitations of using the ball and stick model for DNA, is that within a single double stranded segment of DNA, one would have to use many many balls to represent atoms that are present in the sugar phosphate backbone, along with all of the main atoms that compose the nitrogenous bases of DNA, we also cannot construct or show the helical form of DNA, by using balls and sticks as well.
The Hennessey Venom GT<span> is the fastest road car in the world.
</span>The fastest land animal<span> is the </span>Cheetah
Usain Bolt, the World's fastest<span> man.
</span>The Lockheed SR-71<span> "</span>Blackbird<span>" the fastest airplane.</span>
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