Explore a diverse range of topics and get answers from knowledgeable individuals on IDNLearn.com. Discover prompt and accurate responses from our experts, ensuring you get the information you need quickly.

What is the de Broglie wavelength of an electron with a kinetic energy of 60 eV?

Sagot :

Certainly! Let's determine the de Broglie wavelength of an electron given its kinetic energy of 60 cV (centivolts).

### Step-by-Step Solution:

1. Convert the kinetic energy from cV to Joules:
Since 1 centivolt (cV) is equivalent to [tex]\(1.6 \times 10^{-19}\)[/tex] Joules (as 1 electronvolt (eV) is [tex]\(1.6 \times 10^{-19}\)[/tex] Joules and 1 cV is 0.01 eV), we can convert the kinetic energy:
[tex]\[ \text{Kinetic energy in Joules} = 60 \, \text{cV} \times 1.6 \times 10^{-19} \, \text{J/cV} \][/tex]
[tex]\[ \text{Kinetic energy in Joules} = 9.6 \times 10^{-18} \, \text{J} \][/tex]

2. Determine the velocity of the electron:
Using the kinetic energy formula for non-relativistic speeds:
[tex]\[ KE = \frac{1}{2} m v^2 \][/tex]
where [tex]\(m\)[/tex] is the mass of the electron ([tex]\(9.10938356 \times 10^{-31}\)[/tex] kg). Solving for [tex]\(v\)[/tex]:
[tex]\[ v = \sqrt{\frac{2 \times KE}{m}} \][/tex]
Substituting the known values:
[tex]\[ v = \sqrt{\frac{2 \times 9.6 \times 10^{-18}}{9.10938356 \times 10^{-31}}} \][/tex]
[tex]\[ v \approx 4590987.601589642 \, \text{m/s} \][/tex]

3. Calculate the de Broglie wavelength:
The de Broglie wavelength ([tex]\(\lambda\)[/tex]) is given by:
[tex]\[ \lambda = \frac{h}{p} \][/tex]
where [tex]\(h\)[/tex] is Planck's constant ([tex]\(6.62607015 \times 10^{-34}\)[/tex] Js) and [tex]\(p\)[/tex] is the momentum of the electron ([tex]\(p = m \cdot v\)[/tex]). First, calculate the momentum:
[tex]\[ p = m \times v \][/tex]
[tex]\[ p = 9.10938356 \times 10^{-31} \times 4590987.601589642 \][/tex]
[tex]\[ p \approx 4.181801772 \times 10^{-24} \, \text{kg m/s} \][/tex]
Now, calculate the wavelength:
[tex]\[ \lambda = \frac{6.62607015 \times 10^{-34}}{4.181801772 \times 10^{-24}} \][/tex]
[tex]\[ \lambda \approx 1.5843857242663138 \times 10^{-10} \, \text{m} \][/tex]

### Conclusion:
The de Broglie wavelength of an electron with a kinetic energy of 60 cV is approximately [tex]\(1.584 \times 10^{-10}\)[/tex] meters.