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Wave Optics

Question
CBSEENPH12039928
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Electrons used in an electron microscope are accelerated by a voltage of 25 kV. If the voltage is increased to 100 kV then the de - Broglie wavelength associated with the electrons would

  • decrease by 2 times

  • decrease by 4 times

  • increase by 4 times

  • increase by 2 times

Solution

A.

decrease by 2 times

We have
straight lambda space equals space fraction numerator 12.27 over denominator square root of straight V end fraction So comma straight lambda subscript 1 over straight lambda subscript 2 space equals space square root of straight V subscript 2 over straight V subscript 1 end root straight lambda subscript 1 space equals space straight lambda subscript 2 space square root of straight V subscript 2 over straight V subscript 1 end root straight lambda subscript 1 space equals space straight lambda subscript 2 space square root of 25 over 100 end root straight lambda subscript 1 space equals space straight lambda subscript 2 space square root of 1 fourth end root space equals space straight lambda subscript 1 over 2

Some More Questions From Wave Optics Chapter

Answer the following questions, which help you understand the difference between Thomson's model and Rutherford's model better.
Is the probability of backward scattering (i.e., scattering of α-particles at angles greater than 90°) predicted by Thomson's model much less, about the same, or much greater than that predicted by Rutherford's model?

Answer the following questions, which help you understand the difference between Thomson's model and Rutherford's model better.
Keeping other factors fixed, it is found experimentally that for small thickness t, the number of α-particles scattered at moderate angles is proportional to t. What clue does this linear dependence on t provide?

Answer the following questions, which help you understand the difference between Thomson's model and Rutherford's model better.
In which model is it completely wrong to ignore multiple scattering for the calculation of average angle of scattering of α-particles by a thin foil?

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