Physics · 2019
JEE Main · 11 January 2019, Shift 1 · Q25
If the deBroglie wavelength of an electron is equal to 10^-3 times the wavelength of a photon of frequency 6 × 10^14 Hz, then the speed of electron…
If the deBroglie wavelength of an electron is equal to $\displaystyle 10^{-3}$ times the wavelength of a photon of frequency $\displaystyle 6 \times 10^{14} \mathrm{~Hz}$, then the speed of electron is equal to :
(Speed of light $\displaystyle =3 \times 10^8 \mathrm{~m} / \mathrm{s}$
Planck's constant $\displaystyle =6.63 \times 10^{-34} \mathrm{~J} . \mathrm{s}$
Mass of electron $\displaystyle =9.1 \times 10^{-31} \mathrm{~kg}$ )
Official answer
(2)
$\displaystyle 1.45 \times 10^6 \mathrm{~m} / \mathrm{s}$
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JEE Main 2019 Physics question, with the answer from NTA’s final answer key. Where our answers come from.