What is the de Broglie wavelength associated with an elector accelerated through a potential difference of 144 V? |
0.0102 nm 1.022 nm 0.0102 m 0.102 nm |
0.102 nm |
The correct answer is Option (4) → 0.102 nm ## The de Broglie wavelength ($\lambda$) for an electron accelerated through a potential $V$ is given by: $\lambda = \frac{h}{\sqrt{2mqV}}$ By substituting the standard values for an electron ($h$ = Planck's constant, $m$ = mass of electron, $q$ = charge of electron), we get the simplified formula: $\lambda = \frac{12.27}{\sqrt{V}}Å \quad \text{or} \quad \lambda = \frac{1.227}{\sqrt{V}} \text{ nm}$ Calculation for $V = 144 V$: First, find the square root of the voltage: $\sqrt{144} = 12$. Substitute this into the formula: $\lambda = \frac{1.227}{12} \text{ nm}$ $\lambda = 0.10225 \text{ nm}$ Rounding to three decimal places, we get 0.102 nm. |