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Question: Answered & Verified by Expert
A proton and alpha particle are accelerated through the same potential difference. The ratio of the de-Broglie wavelength of proton to that of alpha will be (mass of alpha particle is four times mass of proton.)
PhysicsDual Nature of MatterMHT CETMHT CET 2021 (21 Sep Shift 2)
Options:
  • A $1: 2$
  • B $2 \sqrt{2}: 1$
  • C $1: 1$
  • D $2: 1$
Solution:
1587 Upvotes Verified Answer
The correct answer is: $2 \sqrt{2}: 1$
De-Broglie wavelength is given by
$$
\lambda=\frac{\mathrm{h}}{\sqrt{2 \mathrm{mqV}}}
$$
If $\lambda_1$ and $\lambda_2$ are de-Broglie wavelengths of proton and alpha particle then
$$
\frac{\lambda_1}{\lambda_2}=\sqrt{\frac{\mathrm{m}_2 \mathrm{q}_2}{\mathrm{~m}_1 \mathrm{q}_1}}=\sqrt{4 \times 2}=\sqrt{8}=2 \sqrt{2}
$$

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