Find the de Broglie wavelength of an electron accelerated through a potential difference of 100 V — JEE Physics
Find the de Broglie wavelength of an electron accelerated through a potential difference of 100 V. (m = 9.1 × 10⁻³¹ kg)
1 Answer
VAVidaara Admin
✓ Vidaara Team
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· 1mo ago
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$$KE = eV = 1.6\times10^{-19} \times 100 = 1.6\times10^{-17} J$$
$$p = \sqrt{2mKE} = \sqrt{2 \times 9.1\times10^{-31} \times 1.6\times10^{-17}} = \sqrt{2.912\times10^{-47}}$$
$$p = 5.4 \times 10^{-24} kg·m/s$$
$$\lambda = \frac{h}{p} = \frac{6.63\times10^{-34}}{5.4\times10^{-24}} \approx 1.23 \times 10^{-10} m = 1.23 Å$$
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Discussion (4)
VN
This finally made it click for me — thank you!
AK
For revision — the key formula used here comes up almost every year.
M
I solved it a slightly different way and got the same answer, good sign.
RV
Clean and to the point. Bookmarking this for revision.