The famous Davisson Germer electron diffraction experiment was performed due to the lack of explanation of an atomic model's wave nature's properties. In 1927 scientists C.J. Davisson and L.H. Germer carried out an experiment to explain an electron's wave nature. This was proposed through electron diffraction method.
This section discusses the experiment and its observation in a detailed manner. The explanations are lucid in nature to help students understand the concepts better. This topic carries heavy weightage in term of marks in the examination.
With a thorough reading, students can solve the variables and equations related to Davisson Germer experiment easily.
Davisson and Germer Experiment on Electron Diffraction Result
Under the Davisson Germer electron diffraction experiment, a student can get the value of scattering angle θ. They can also find the possible difference V's equivalent value at which electrons' scattering is the highest. The data collected by Davisson and Germer gives two theories or an equation that again shows the same value for λ. If we include De Broglie's duality in a wave-particle, there can be two equations (a) and (b).
The equation that substantiates the De Broglie's wave-particle duality is –
λ = h/√2meV2meV
Here one can find V's value to be 54 V
Now we know that λ = 12.27/√5454 which gives us the value 0.167 nm
If we go through the equation, we find that'd' will have a value of 0.092 nm. It is gained through X-ray scattering. That gives us v's value to be 54 V. The angle of scattering is equal to 500500.
Now applying this value in a second equation, we get that
(b) nλ = 2 (0.092 nm) sin( 900−500/2)900−500/2)
Let's take n's value to be 1, while λ is 0.165 nm
This value finally verifies the theoretical explanation of the De Broglie equation.
Davisson and Germer Electron Diffraction Experiment Observation
To find the presence of an electron in a particle form, a student can use a detector. Davisson Germer electron diffraction experiment indicates that a detector receives electronic current, i.e. electron. Here the strength or intensity of an electric current produced or received and scattered in an angle is studied. This current referred to as electron intensity.
Another observation that students can find here explains how the intensity of a scattered electron is never continuous. One can find both minimum and maximum value analogous to the utmost and least diffraction pattern gained via X-rays.
Scattered electrons have continuous intensity levels, which displays a maximum and the least analogous value to the utmost, and minimum value of a diffraction pattern created by X-rays. This value can be found by studying potential differences and scattering angles.
The Setup of Davisson Germer Experiment
Lastly, under this Davisson Germer electron diffraction experiment, a student can understand the setup formed. Ideally, the thought behind this elaborate experiment was the nature of wave particles reflected.
Davisson and Germer's experiment shows that waves reflected in a Ni crystal that passes two atomic layers contain a constant phase disparity. Students can learn that after reflection, these waves encumber annihilation or construction. This gives rise to the famous diffraction pattern.
It is seen that during the Davisson and Germer experiment, electrons are replaced with wave particles. These electrons combined to form a diffraction pattern. Finally, producing the ultimate result, which is the dual nature of matter.
Davisson Germer experiment electron diffraction chapter is complicated in terms of equation and usage. A student needs to have a clear understanding of the basic topics that carry high marks. This complex topic requires students to depend on guidebooks and study materials that offer only exercises not a valid explanation.
FAQs on Davisson Germer Experiment
1. What is the main objective of the Davisson Germer Experiment in understanding the nature of particles?
The main objective of the Davisson Germer Experiment was to demonstrate the wave nature of electrons by observing electron diffraction, thus confirming the de Broglie hypothesis that matter exhibits both particle and wave properties, as required in the CBSE 2025–26 Physics syllabus.
2. How does the Davisson Germer Experiment support the concept of matter waves?
The experiment showed that when electrons are scattered off a nickel crystal, they produce a diffraction pattern similar to X-rays, supporting de Broglie's theory that matter particles like electrons can act as waves with wavelength λ = h/p, where h is Planck’s constant and p is momentum.
3. Explain the experimental setup and key observations of the Davisson Germer Experiment.
The setup includes an electron gun, a nickel crystal target, and a detector rotating to detect scattered electrons. Key observations were:
- Peak intensity of scattered electrons at specific angles, indicating constructive interference.
- Observed pattern matched theoretical predictions for electron wavelength, confirming wave behaviour.
4. Why was the use of a nickel crystal significant in the Davisson Germer Experiment?
The nickel crystal provided a regular atomic arrangement, acting as a 3D diffraction grating. This allowed incident electrons to produce measurable diffraction patterns, making the wave nature of electrons observable and supporting the physics curriculum expectations.
5. What mathematical relationship derived from the experiment connects electron wavelength to crystal spacing?
Using Bragg’s Law: nλ = 2d sinθ, where λ is the electron wavelength, d is the lattice spacing, θ is the scattering angle, and n is the order of maximum. The measured diffraction angles matched the values predicted for the calculated de Broglie wavelength.
6. How did the results of the Davisson Germer Experiment impact the acceptance of quantum mechanics?
The clear evidence of electron diffraction strongly supported the concept of wave-particle duality. This played a vital role in the development and acceptance of quantum mechanics in modern physics, as emphasised in the CBSE/NCERT exam pattern.
7. What conceptual errors should students avoid when studying the Davisson Germer Experiment for board exams?
Students should avoid the misconception that electrons always behave like particles. The experiment proves that under certain conditions, electrons behave as waves. Additionally, don’t confuse the experiment with the photoelectric effect, which deals with photon emission and not electron diffraction.
8. How can one differentiate between the photoelectric effect and the Davisson Germer Experiment in CBSE examinations?
- Photoelectric effect shows the particle nature of light (photons causing electron emission).
- Davisson Germer Experiment demonstrates the wave nature of electrons (electron diffraction).
9. Why is the Davisson Germer Experiment essential for understanding modern technologies such as electron microscopes?
The wave nature of electrons confirmed by this experiment allows for their use in electron microscopes, where electron diffraction enables imaging of structures much smaller than visible light allows, thus explaining the practical application required by the CBSE Physics syllabus.
10. What potential exam questions can be expected from the Davisson Germer Experiment according to recent CBSE trends?
Expected exam questions may include:
- Derivation or explanation of electron diffraction based on de Broglie hypothesis
- Describing the experimental setup and significance
- Application of Bragg’s law to the data
- Comparing wave and particle nature in different experiments
- Importance in the evolution of quantum mechanics
