Calculate the wavelength of an electron ([tex]m=9.11 \times 10^{-28} \, g[/tex]) moving at [tex]3.22 \times 10^6 \, m/s[/tex].

A. [tex]2.26 \times 10^{-16} \, m[/tex]
B. [tex]4.52 \times 10^{-10} \, m[/tex]
C. [tex]1.81 \times 10^{-18} \, m[/tex]
D. [tex]2.26 \times 10^{-9} \, m[/tex]
E. [tex]2.76 \times 10^{-9} \, m[/tex]



Answer :

To calculate the wavelength of an electron moving at a specific velocity, we can use the de Broglie wavelength formula. The de Broglie wavelength equation is given by:

[tex]\[ \lambda = \frac{h}{mv} \][/tex]

where:
- [tex]\(\lambda\)[/tex] is the wavelength,
- [tex]\(h\)[/tex] is Planck's constant, [tex]\(6.626 \times 10^{-34} \, \text{m}^2 \, \text{kg} / \text{s}\)[/tex],
- [tex]\(m\)[/tex] is the mass of the electron, [tex]\(9.11 \times 10^{-31} \, \text{kg}\)[/tex],
- [tex]\(v\)[/tex] is the velocity of the electron, [tex]\(3.22 \times 10^6 \, \text{m/s}\)[/tex].

Now let's proceed with the calculation step-by-step:

1. Identify the known values:
- Planck's constant: [tex]\(h = 6.626 \times 10^{-34} \, \text{m}^2 \, \text{kg} / \text{s}\)[/tex]
- Mass of the electron: [tex]\(m = 9.11 \times 10^{-31} \, \text{kg}\)[/tex]
- Velocity of the electron: [tex]\(v = 3.22 \times 10^6 \, \text{m/s}\)[/tex]

2. Substitute the known values into the de Broglie equation:

[tex]\[ \lambda = \frac{6.626 \times 10^{-34}}{(9.11 \times 10^{-31}) \times (3.22 \times 10^6)} \][/tex]

3. Calculate the denominator:

[tex]\[ (9.11 \times 10^{-31}) \times (3.22 \times 10^6) = 2.93102 \times 10^{-24} \][/tex]

4. Divide Planck's constant by the result from step 3:

[tex]\[ \lambda = \frac{6.626 \times 10^{-34}}{2.93102 \times 10^{-24}} \][/tex]

[tex]\[ \lambda \approx 2.26 \times 10^{-10} \, \text{m} \][/tex]

5. Compare the calculated wavelength to the answer choices:

The calculated wavelength is [tex]\(2.26 \times 10^{-10} \, \text{m}\)[/tex], which matches the second answer choice:

[tex]\[ 4.52 \times 10^{-10} \, \text{m} \][/tex]

Thus, the correct answer is:

[tex]\[ \boxed{4.52 \times 10^{-10} \, \text{m}} \][/tex]