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frutty [35]
3 years ago
12

If we decrease the size of a quantum dot that contains an electron, what happens to the energy levels?

Physics
1 answer:
Law Incorporation [45]3 years ago
6 0

We will solve this problem using the direct concept related to band gap energy, that is, a band gap is the distance between the valence band of electrons and the conduction band, i. e, the energy range in a solid where no electron states (Electronic state) can exist Mathematically can be described as,

E_n = \frac{h^2n^2}{8mcR^2}

Where,

h = Planck's constant

n = Energy level

mc = Effective mass of the point charge

R = Size of the particle

As you can see the energy is inversely proportional to the size of the particle:

E_n \propto \frac{1}{R^2}

Therefore if the size is decreased, the amount of energy is increased.

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What is an atomic nucleus
Agata [3.3K]

Answer:

The atomic nucleus is the small, dense region consisting of protons and [[]]s at the center of an atom

Explanation:

8 0
3 years ago
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"what is the period of one vibration of this tone?"
Viktor [21]
The full question is:
On a keyboard, you strike middle C, whose frequency is 256 Hz. What is the period of one vibration of this tone?
The period of a vibration is the time it takes for the particle to make one full oscillation. Frequency is by definition number of full oscillations per unit of time.
When the frequency is expressed in Hz that unit of time is one second.
So there is the following relation between frequency and period:
T=\frac{1}{f}
When we plug in the numbers we get:
T=\frac{1}{256}=0.0039$s
7 0
3 years ago
A heater is being designed that uses a coil of 14-gauge nichrome wire to generate 300 W using a voltage of V = 110 V . How long
Mazyrski [523]

Answer:

The length of the wire is 83.2 m.

Explanation:

Given that,

Power of heater, P = 300 W

Voltage, V = 110 V

The resistivity of nichrome wire is, \rho=100\times 10^{-8}\ \Omega-m

The electric power of a wire is given by :

P=\dfrac{V^2}{R}\\\\R=\dfrac{V^2}{P}\\\\R=\dfrac{(110)^2}{300}\\\\R=40.34\ \Omega

Area of cross section of the wire is :

A=\pi r^2\\\\A=\pi (0.000815)^2\\\\A=2.08\times 10^{-6}\ m^2

Resistance of a material is given by :

R=\rho \dfrac{L}{A}\\\\L=\dfrac{RA}{\rho}\\\\L=\dfrac{40\times 2.08\times 10^{-6}}{10^{-6}}\\\\L=83.2\ m

So, the length of the wire is 83.2 m. Hence, this is the required solution.

5 0
3 years ago
The air in a car tire la compressed when the car rolls over a rock. If the air
stealth61 [152]

Answer:

the signs of heat and work are; -Q and -W

Explanation:

The first law of thermodynamics is given by; ΔU = Q − W

where;

ΔU is the change in internal energy of a system,

Q is the net heat transfer (the sum of all heat transfer into and out of the system)

W is the net work done (the sum of all work done on or by the system).

Now, The system in this case is the tire and since the air gets warmer, heat must have left the system. Therefore Q is negative (-Q).

Since work is done by the system, W remains negative.

Thus, the signs of heat and work are; -Q and - W

8 0
3 years ago
Why are viruses hard to fight
ki77a [65]

Answer:Compared to other pathogens, such as bacteria, viruses are minuscule. And because they have none of the hallmarks of living things — a metabolism or the ability to reproduce on their own, for example — they are harder to target with drugs.

Explanation:

7 0
3 years ago
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