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JEE Main 2020 (9 Jan, Shift 2) · Matter Waves: de Broglie Wavelength

Matter Waves: de Broglie Wavelength question from JEE Main 2020 (9 Jan, Shift 2)

Q118JEE Main 2020 · 9 JAN · SHIFT 2Difficult

Matter Waves: de Broglie Wavelength

An electron of mass m and magnitude of charge |e| initially at rest gets accelerated by a constant electric field E. The rate of change of de-Broglie wavelength of this electron at time t ignoring relativistic effects is:

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Answer: (c)

  1. From rest under constant force ∣e∣E|e|E: p=∣e∣Etp = |e|Et.
  2. λ=h∣e∣Et⇒dλdt=−h∣e∣Et2\lambda = \dfrac{h}{|e|Et} \Rightarrow \dfrac{d\lambda}{dt} = \dfrac{-h}{|e|Et^2}
  3. So the answer is (c).
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