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Grade 12Wave Optics

A parallel beam of electrons travelling in
x-direction falls on a slit of width d (see
figure). If after passing the slit, an electron
acquires momentum py in the y-direction
then for a majority of electrons passing
through the slit (h is Planck’s constant) .Please explain me the answer of this question.

Question image for A parallel beam of electrons travelling in x-dire
Profile image of kshitij
8 Years agoGrade 12
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1 Answer

Profile image of Arun
8 Years ago

As we learnt in

Fraunhofer Diffraction -

b\sin \theta = n\lambda

- wherein

Condition of nth minima.

b= slit width

\theta = angle of deviation

dsin\theta=\lambda\ \; \Rightarrow\ \;sin\theta=\frac{\lambda}{d}<1

\lambda<d\ \; \left[\lambda=\frac{h}{[P_{y}]} \right ]

\frac{h}{[P_{y}]}<d

\therefore\ \; h<|P_{y}|d

|P_{y}|d<h

Correct option is 3.