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Tju [1.3M]
3 years ago
7

Do the conduction electrons in a copper wire act quantum mechanically or not? Roughly speaking, quantum mechanics comes in when

the de Broglie wavelength of an electron is comparable to or longer than the spacing between atoms. The lattice constant (roughly the spacing between atoms in a crystal) for copper is about 4 x 10-10 m. The drift velocity of electrons is typically less than 102 m/s under household conditions (b) What about atoms in the interstellar medium? Here we want to compare the average spacing between atoms (they move!) to the de Broglie wavelength of an atom. The interstellar medium is mostly hydrogen at an average density of order 1/cm3 and temperature about 3 K. In this case you' need the thermody- namic resul p/(2m)(3/2)kT, where k is Boltzmann's constant (c) Now let's switch gears to talk abou the Uncertainty Principle When LIGO detects gravitational waves, it is measuring displacements of its test masses of order 10-18 m. The test masses are about 40 kg. What is the minimum uncertainty induced in the velocities of the test masses?
Physics
1 answer:
Ksju [112]3 years ago
6 0

Answer:

I know the answer

Explanation:

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An electric current is flowing through a long cylindrical conductor with radius a. The current density J is uniform in the cylin
RUDIKE [14]

Answer:

Check the explanation

Explanation:

Kindly check the attached images below to see the step by step explanation to the question above.

4 0
3 years ago
A spy camera is said to be able to read the numbers on a car's license plate. If the numbers on the plate are 4.30 cm apart, and
Maslowich

Answer:

D = 2.38 m

Explanation:

This exercise is a diffraction problem where we must be able to separate the license plate numbers, so we must use a criterion to know when two light sources are separated, let's use the Rayleigh criterion, according to this criterion two light sources are separated if The maximum diffraction of a point coincides with the first minimum of the second point, so we can use the diffraction equation for a slit

         a sin θ  = m λ

Where the first minimum occurs for m = 1, as in these experiments the angle is very small, we can approximate the sine to the angle

           θ = λ / a

Also when we use a circular aperture instead of slits, we must use polar coordinates, which introduce a numerical constant

           θ = 1.22 λ / D

Where D is the circular tightness

       

Let's apply this equation to our case

         D = 1.22 λ /  θ

To calculate the angles let's use trigonometry

         tan  θ = y / x

          θ = tan⁻¹  y / x

          θ = tan⁻¹ (4.30 10⁻² / 140 10³)

          θ = tan⁻¹ (3.07 10⁻⁷)

          θ = 3.07 10⁻⁷ rad

Let's calculate

        D = 1.22 600 10⁻⁹ / 3.07 10⁻⁷

        D = 2.38 m

4 0
3 years ago
Read 2 more answers
Just want a ride with​
yaroslaw [1]

Answer:

My best friend lol cuz since quarantine i didn't see her

8 0
3 years ago
Which process is an example of a physical change?
Anit [1.1K]

Answer:

Option A

Carrots are cut into small pieces and mixed into a salad

Explanation:

When physical changes occur, the actual composition remain the same but the molecules are re-arranged. Therefore, when carrots are cut into smaller pieces and mixed into salad, there will be no chemical reaction hence the actual composition will remain the same despite being cut and molecules in it re-arranged. Considering the other options, new substances are formed hence they are deemed as chemical changes. Therefore, option A is correct.

8 0
3 years ago
A particle travels clockwise on a circular path of diameter​ R, monitored by a sensor on the circle at point​ P; the other endpo
kotykmax [81]

We make a graphic of this problem to define the angle.

The angle we can calculate through triangle relation, that is,

sin\theta = \frac{c}{QP}\\sin\theta = \frac{c}{R}\\\theta=sin^{-1}\frac{c}{R}

With this function we should only calculate the derivate in function of c

\frac{d\theta}{dc} = \frac{1}{\sqrt{1-\frac{c^2}{R^2}}}(\frac{c}{R})'\\\frac{d\theta}{dc} = \frac{1}{\sqrt{R^2-c^2}}

That is the rate of change of \theta.

b) At this point we need only make a substitution of 0 for c in the equation previously found.

\frac{d\theta}{dc}\big|_{c=0} = \frac{1}{\sqrt{R^2-0}}\\\frac{d\theta}{dc}\big|_{c=0} = \frac{1}{R}

Hence we have finally the rate of change when c=0.

6 0
3 years ago
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