If the momentum of an electron is changed by P, then the de Broglie wavelength associated with it changes by…

If the momentum of an electron is changed by P, then the de Broglie wavelength associated with it changes by 0.5%. The initial momentum of electron will be
A 100 P
B 200 P
C 400 P
D $\frac{P}{200}$

Detailed Solution

$\lambda = \frac{h}{p}$, so for small changes $\frac{\Delta p}{p} = \frac{\Delta\lambda}{\lambda}$ (in magnitude)
Here $\Delta p = P$ and $\frac{\Delta\lambda}{\lambda} = \frac{0.5}{100}$
$\frac{P}{p} = \frac{0.5}{100} \Rightarrow p = 200P$

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Practise de Broglie Wavelength All 12 questions This chapter in 2012 AIPMT-MAINS