To calculate the wavelength of an electron, we use the de Broglie wavelength formula:

To calculate the wavelength of an electron, we use the de Broglie wavelength formula:

$$\lambda = \frac{h}{mv}$$

where:

• $\lambda$ is the de Broglie wavelength
• $h$ is Planck's constant ($6.626 \times 10^{-34} \, \text{J} \cdot \text{s}$)
• $m$ is the mass of the electron ($9.109 \times 10^{-31} \, \text{kg}$)
• $v$ is the speed of the electron ($4.2 \times 10^7 \, \text{m/s}$)

Step 1: Substitute the given values into the formula.

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