NEET
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- NEET
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- Physics
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- Atomic Physics
NEET · Physics · Atomic Physics
Given below are two statements: One is labelled as Assertion (A)...
Given below are two statements: One is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : In Davisson-Germer experiment wavelength associated with the beam decreases with increases of speed of electrons.
Reason (R) : Wavelength associated with electron beam in Davission-Germer experiment is given by (\lambda=\frac{\mathrm{h}}{\sqrt{2 \mathrm{mK}}})
In the light of the above statements, choose the most appropriate answer from the options given below:
Options
- ABoth (A) and (R) are true and (R) is the correct explanation of (A).
- BBoth (A) and (R) are true and (R) is NOT the correct explanation of (A).
- C(A) is true but (R) is false.
- D(A) is false but (R) is true.
Correct answer
C. (A) is true but (R) is false.
Step-by-step solution
- Assertion (A): In the Davisson-Germer experiment, the wavelength associated with the electron beam indeed decreases with the increase in the speed of electrons. This follows from de Broglie's equation, (\lambda=), where is the speed of the electrons. As the speed increases, the wavelength decreases, making the assertion true.
- Reason (R): The equation (\lambda=) is incorrect. The correct form of de Broglie's wavelength is (\lambda=) where is the momentum of the electron, or (\lambda=), where is the kinetic energy of the electron.