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3 years ago

Hi:) why do metals have free electrons? anyone able to explain the conduction part as well? Thanks!

Physics

1 answer:

Karo-lina-s [1.5K]3 years ago

7 0

Metals have free electrons due to the bonding in metallic substances.

In a metal there are strong attractive forces between the nuclei and the valance electrons.

Positively charged metal nuclei form a lattice (a cube like structure) each metal atom provides one or more valance electrons that are free to move throughout the lattice The electrons are attracted to the positively charged nuclei but not one individual nuclei, this is called non-directional bonding since it occurs in all directions.

Now all metals are conductive becuase of the free to move (delocalised) electrons. Since the valance electrons are free to move throughout the lattice they are able to carry a charge. (Ionic solids cannot since the ionic solids form a tightly packed lattice with cations and anions which have no free moving electrons, electrons have to be able to move to carry a charge)

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Polarized light passes through a polarizer. If the electric vector of the polarized light is horizontal what, in terms of the in

Nina [5.8K]

Answer:

The intensity of the light that passes through a polarizer is 0.55I₀.

Explanation:

The intensity of the light that passes through a polarizer can be found using Malus's law:

$I = I_{0}cos^{2}(\theta)$

Where:

I: is the intensity of the light that passes through a polarizer

I₀: is the initial intensity

θ: is the angle between the light's initial polarization direction and the axis of the polarizer = 42°

$I = I_{0}cos^{2}(\theta) = I_{0}cos^{2}(42) = 0.55*I_{0}$

Therefore, the intensity of the light that passes through a polarizer is 0.55I₀.

I hope it helps you!

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3 years ago

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Answer:

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Explanation:

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Which of the following must be transformed into electrical energy when biomass is used as an energy resource?

dangina [55]

It’s chemical energy

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4 years ago

The range and standard deviation of a distribution are __________.

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Determine the moment of inertia Ixx of the mallet about the x-axis. The density of the wooden handle is 860 kg/m3 and that of th

Yuki888 [10]

Complete Question

Diagram for this shown on the first uploaded image

Answer:

The moment of inertia Ixx of the mallet about the x-axis is $I{xx}= 0.119 kg \cdot m^2$

Explanation:

From the question we are told that

The density `of wooden handle is $\rho_w = 860 kg/m^3$

The density `of soft-metal head is $\rho_s =8000kg/m^3$

Generally the mass of the wooden can be mathematically obtained with this formula

$m_w = \rho_w A_w l_w$

Where $A_w$ is mass of wooden handle which is mathematically obtain with the formula

$A_w = \frac{\pi}{4} d^2_w$

Where $d_w$ is the diameter of the wooden handle which from the diagram is

$27mm = \frac{27}{1000} = 0.027m$

So $A_w = \frac{\pi}{4} * 0.027^2$

$l_w$ is the length of the the wooden handle which is given in the diagram as $l_w = 315mm = \frac{315}{1000} = 0.315m$

Substituting these value into the formula for mass

$m_w = 860 * (\frac{\pi}{4} * 0.027^2 ) *0.315$

$= 0.155kg$

Generally the mass of the soft-metal head can be mathematically obtained with this formula

$m_s = \rho_s A_s l_s$

Where $A_s$ is mass of soft-metal head which is mathematically obtain with the formula

$A_s = \frac{\pi}{4} d^2_s$

Where $d_s$ is the diameter of the soft-metal head which from the diagram is

$36mm = \frac{36}{1000} = 0.036m$

So $A_s = \frac{\pi}{4} * 0.036^2$

$l_s$ is the length of the the soft-metal head which is given in the diagram

as $l_s = 90mm = \frac{90}{1000} = 0.090m$

Substituting these value into the formula for mass

$m_s = 8000 * (\frac{\pi}{4} * 0.036^2 ) *0.090$

$=0.733kg$

Generally the mass moment of inertia about x-axis for the wooden handle is

$(I_{xx})_w = [\frac{1}{3}m_w + l_w^2 ]$

Substituting values

$(I_{xx})_w = [\frac{1}{3}*0.155 + 0.315^2 ]$

$=5.12*10^{-3}kg \cdot m^2$

Generally the mass moment of inertia about x-axis for the soft-metal head is

$(I_{xx})_s = [\frac{1}{12}m_s l_s ^2 + b^2]$

Where b is the distance from the centroid to the axis of the head which is mathematically given as

$b=l_w +\frac{d_s}{2}$

Substituting values

$b = 0.315 + \frac{0.036}{2}$

$= 0.336m$

Now substituting values into the formula for mass moment of inertia about x-axis for soft-metal head

$(I_{xx})_s = [\frac{1}{12} *0.733* 0.090^2 + 0.336^2]$

$=0.113 kg \cdot m^2$

Generally the mass moment of inertia about x-axis is mathematically represented as

$I_{xx} = (I_{xx})_w + (I_{xx})_s$

$= [\frac{1}{3}m_w + l_w^2 ] + [\frac{1}{12}m_s l_s ^2 + b^2]$

Substituting values

$I_{xx} = 5.12*10^{-3} +0.113$

$I{xx}= 0.119 kg \cdot m^2$

8 0

3 years ago