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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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a rectangular block weighs 240N. The area of the block in contact with the floor is 20cm2 calculate the pressure on the floor
Romashka [77]

Answer:

The pressure on the floor is 12 Pascal(Pa).

Explanation:

Given,

Force (F) = 240N

Area (A) = 20 cm^2

Pressure (P) = ?

we know that,

P = F/A

= 240/ 20

= 12 Pa

8 0
3 years ago
Which object has more gravitational potential energy? Use PE = m × g × h, where g = 9.8 meters/second2.
Andrew [12]
Gravitational potential energy can be calculated using the formula <span>PE = m × g × h, where g is the gravitational acceleration and is constant hence the energy is dependent directly to mass and the height of the object. Hence more PE is registered when the object is heavier and/or at greater initial height. </span>
6 0
3 years ago
Read 2 more answers
Carlos is making phosphorous trichloride using the equation below. He adds 15 g of phosphorus.
Degger [83]
Given:

The balanced chemical reaction of the synthesis of phosphorus trichloride:

2P + 3Cl2 ===> 2PCl3

Initial amount of phosphorus = 15 grams

The amount of product produced from 15 grams of phosphorus:

15 grams / 31 g/mol * (2/2) = 66.46 grams PCl3 

The amount of chlorine is 44.31 grams, nearest to 45 grams. 
8 0
4 years ago
Read 2 more answers
A parallel-plate capacitor is charged by connecting it to a battery. If the battery is disconnected and then the separation betw
TEA [102]

Answer:

The charge stored in the capacitor will stay the same. However, the electric potential across the two plates will increase. (Assuming that the permittivity of the space between the two plates stays the same.)

Explanation:

The two plates of this capacitor are no longer connected to each other. As a result, there's no way for the charge on one plate to move to the other. Q, the amount of charge stored in this capacitor, will stay the same.

The formula \displaystyle Q = C\, V relates the electric potential across a capacitor to:

  • Q, the charge stored in the capacitor, and
  • C, the capacitance of this capacitor.

While Q stays the same, moving the two plates apart could affect the potential V by changing the capacitance C of this capacitor. The formula for the capacitance of a parallel-plate capacitor is:

\displaystyle C = \frac{\epsilon\, A}{d},

where

  • \epsilon is the permittivity of the material between the two plates.
  • A is the area of each of the two plates.
  • d is the distance between the two plates.

Assume that the two plates are separated with vacuum. Moving the two plates apart will not affect the value of \epsilon. Neither will that change the area of the two plates.

However, as d (the distance between the two plates) increases, the value of \displaystyle C = \frac{\epsilon\, A}{d} will become smaller. In other words, moving the two plates of a parallel-plate capacitor apart would reduce its capacitance.

On the other hand, the formula \displaystyle Q = C\, V can be rewritten as:

V = \displaystyle \frac{Q}{C}.

The value of Q (charge stored in this capacitor) stays the same. As the value of C becomes smaller, the value of the fraction will become larger. Hence, the electric potential across this capacitor will become larger as the two plates are moved away from one another.  

3 0
3 years ago
A 4.0 kg circular disk slides in the x- direction on a frictionless horizontal surface with a speed of 5.0 m/s as shown in the a
finlep [7]

Solution :

Let $m_1=m_2=4$ kg

$u_1 = 5$ m/s

Let $v_1$ and $v_2$ are the speeds of the disk $m_1$ and $m_2$  after the collision.

So applying conservation of momentum in the y-direction,

$0=m_1 .v_1_y -m_2 .v_2_y $

$v_1_y = v_2_y$

$v_1 . \sin 60=v_2. \sin 30$

$v_2 = v_1 \times \frac{\sin 60}{\sin 30}$

$v_2=1.732 \times v_1$

Therefore, the disk 2 have greater velocity and hence more kinetic energy after the collision.

Now applying conservation of momentum in the x-direction,

$m_1.u_1=m_1.v_1_x+m_2.v_2_x$

$u_1=v_1_x+v_2_x$

$5=v_1. \cos 60 + v_2 . \cos 30$

$5=v_1. \cos 60 + 1.732 \times v_1 \cos 30$

$v_1 = 2.50$ m/s

So, $v_2 = 1.732 \times 2.5$

          = 4.33 m/s

Therefore, speed of the disk 2 after collision is 4.33 m/s

5 0
3 years ago
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