Dual Nature Of Light Question 344
Question: An electron of mass ’m’ and 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:
Options:
A) $ \frac{-h}{eEt^{2}} $
B) $ \frac{-eht}{E} $
C) $ \frac{-mh}{eEt^{2}} $
D) $ \frac{-h}{eE} $
Show Answer
Answer:
Correct Answer: A
Solution:
[a] Acceleration, $ a=\frac{Ee}{m} $ Velocity of electron, $ v=at=\frac{Eet}{m} $ Wavelength, $ \lambda =\frac{h}{mv}=\frac{h}{Eet}. $ Now $ \frac{d\lambda }{dt}=-\frac{h}{eEt^{2}} $
BETA
