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Nataliya [291]
2 years ago
14

Calculate the number of free electrons and holes (in m-3) in an intrinsic semiconductor that has electron and hole mobilities of

0.35 and 0.17 m2/V-s, respectively, and a conductivity of 1.7 (Ω-m)-1. Use scientific notation.
Physics
1 answer:
allochka39001 [22]2 years ago
5 0

Answer:

ni = 2.04e19

Explanation:

we know that in semiconductor like intrinsic, when electron leave the band, it leave a hole in valence band so we have

n = p = ni

from intrinsic carrier concentration

\sigma = n\left | e \right | \mu_e + n\left | e \right | \mu_h

\sigma = ni\left | e \right | \mu_e  + ni\left | e \right | \mu_h

\sigma = ni \left | e \right | ( \mu_e + \mu_h)

1.7 = ni * 1.6*10^{-19} * (.35 + .17)

ni = 2.014 *10^{19} m^{-3}

ni = 2.04e19

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sammy [17]

Answer:

The doppler effect equation is:

f' = \frac{v +v0}{v - vs}*f

In the equation we have frequencies, but then we have the wavelengths of the lights, remember the relation:

v = f*λ

then:

f = v/λ

and v is the speed of light, then:

f = c/λ

where:

f' is the observed frequency, in this case, is equal to f = (3*10^17nm/s)/550 nm

f is the real frequency, in this case, is (3*10^17nm/s)/650 nm

vs is the speed of the source, in this case, the source is not moving, then vs = 0 m/s.

v is the speed of the wave, in this case, is equal to the speed of light, v = 3*10^8 m/s

v0 is your speed, this is what we want to find.

Replacing those quantities in the equation, we get:

(3*10^17nm/s)/550 = (3*10^8 m/s + v0)/(3*10^8 m/s)*(3*10^17nm/s)/650 nm

(650nm)/(550nm) = (3*10^8 m/s + v0)/(3*10^8 m/s)

1.182*(3*10^8 m/s) = (3*10^8 m/s + v0)

1.182*(3*10^8 m/s) -  (3*10^8 m/s) = v0 = 54,600,000 m/s

So your speed was 54,600,000 m/s, which is a lot.

6 0
3 years ago
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Colt1911 [192]

Answer:

Secrets? Cuz if I share you the secrets then the secrets will no longer will be secrets.

4 0
3 years ago
Read 2 more answers
Choose either eclipses or lunar phases and make a model of the event. Your model can take any form, providing it can explain how
babymother [125]

Answer: See the explanation below.

Explanation: For this assignment, I chose to display how eclipses are created.

My model was made utilizing a 3D displaying device program for all intents and purposes. The items utilized are three models I made for this presentation, Earth, the moon, and the sun. These three models will be utilized for the showcase.  

The light that shines from the sun would create a shadow on the moon. The moon would then catch the light that should've arrived on Earth, making the shadow we call an eclipse. Earth gets a shadow of the moon and the remainder of Earth is lit up from the rest of the light, making an eclipse.  

The individual I demonstrated my project to was [<em>Someone you know</em>], [<em>Pronoun</em>] said it precisely took after the occasion of an eclipse. The light from the sun being shined on to the moon rather than the Earth, creating the shadow we call an eclipse.

5 0
2 years ago
Match the words in the left-hand column to the appropriate blank in the sentences in the right-hand column.
zheka24 [161]

Answer:

1. Molecular cloud

2. Close binary

3. Brown dwarf

4. Protostellar wind

5. Thermal pressure

6. Protostellar disk

7. Jet

8. Degeneracy pressure

Explanation:

1. The Sun formed, probably along with other stars, within a large molecular cloud.

2. A Close binary consists of two stars that orbit each other every few days.

3. A Brown dwarf is a "star" so small in mass that its core never gets hot enough to sustain nuclear fusion reactions.

4. Most of the gas remaining from the process of star formation is swept into interstellar space by a protostellar wind.

5. As a protostar's internal temperature increases, its growing thermal pressure helps slow its contraction due to gravity.

6. Planets may form within the protostellar disk that surrounds a forming star.

7. Mass can be lost through a jet of material ejected along a protostar's axis of rotation.

8. A "star" with mass below 0.08 solar mass has its gravitational contraction halted by degeneracy pressure.

8 0
3 years ago
A body of volume 2000 cm3 has a mass 4 kg. Find the density of the body. Will the body sink or float in water, if the density of
Brums [2.3K]

Answer:

2 g/cm^3, it will sink

Explanation:

The density of an object is given by

d=\frac{m}{V}

where

m is the mass of the object

V is its volume

For the body in the problem, we have

m = 4 kg = 4000 g

V=2000 cm^3

Therefore, its density is

d=\frac{4000}{2000}=2 g/cm^3

And the object will sink in water, because its density is larger than that of water, which is 1 g/cm^3. (an object sinks when its density is larger than that of water, otherwise it floats).

6 0
3 years ago
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