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3. Find the de Broglie wavelength of the following particles: (i) An electron in a semiconductor having average thermal velocity at T = 300 K

Respuesta :

Answer:

The wavelength of the electron is [tex]\dfrac{4.4097\times10^{-9}}{\sqrt{a}}\ m[/tex]

Explanation:

Given that,

Temperature = 300 K

We know that,

The energy of free electron is

[tex]E=\dfrac{(\hbar)^2k^2}{2m}[/tex]

[tex]k=\dfrac{\sqrt{2mE}}{\hbar}[/tex]

Where, k = wave number

The momentum of the electron is

[tex]p=\hbar k[/tex]

Th effective mass is

[tex]m=am_{0}[/tex]

We need to calculate the wavelength of the electron

Using formula of wave number

[tex]k=\dfrac{2\pi}{\lambda}[/tex]

[tex]\lambda=\dfrac{2\pi}{k}[/tex]

Put the value of k

[tex]\lambda=\dfrac{2\pi}{\dfrac{\sqrt{2mE}}{\hbar}}[/tex]

[tex]\lambda=\dfrac{h}{\sqrt{2am_{0}E}}[/tex]

We know that,

Thermal energy of electron

[tex]E=3kT[/tex]

The de Broglie wavelength of the electron is

[tex]\lambda=\dfrac{h}{\sqrt{2am_{0}\times3kT}}[/tex]

Put the value into the formula

[tex]\lambda=\dfrac{6.63\times10^{-34}}{\sqrt{2\times9.1\times10^{-31}\times3\times300\times1.380\times10^{-23}\times a}}[/tex]

[tex]\lambda=\dfrac{4.4097\times10^{-9}}{\sqrt{a}}\ m[/tex]

Hence, The wavelength of the electron is [tex]\dfrac{4.4097\times10^{-9}}{\sqrt{a}}\ m[/tex]

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