Dual Nature Of Radiation And Matter Ques 7
7. If the momentum of electron is changed by $P$, then the de Broglie wavelength associated with it changes by $0.5 \%$. The initial momentum of electron will be :
[2012 M]
(a) $200$ $ P$
(b) $400 $ $P$
(c) $\frac{P}{200}$
(d) $100 $ $P$
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Answer:
Correct Answer: 7.(a)
Solution:
- (a) The de-Broglie’s wavelength associated with the moving electron $\lambda=\frac{h}{P}$
Now, according to the problem
$\frac{d \lambda}{\lambda}=-\frac{d p}{P}$
$\frac{0.5}{100}=\frac{P}{P^{\prime}}$
$P^{\prime}=200 $ $P$
BETA
